超长整数类,C\C++交流,技术交流,鱼C论坛

天涯忘 发表于 2019-1-3 12:35:35

超长整数类

本帖最后由天涯忘于 2019-1-3 12:41 编辑

不能理解这段代码的基本原理具体是什么，求大佬帮具体讲解注释一下，谢谢

#include<iostream>
#include<cstring>
#define MAX 65*65
using namespace std;
class doublelong{
char number;
public:
doublelong(const char *str = " ")
{
strcpy(number, str);
}
void show()
{
cout << number << endl;
}
void operator>>(doublelong a)
{
cin >> number;
}
friend istream & operator>>(istream &is, doublelong &ob);
friend ostream & operator<<(ostream &os, const doublelong &ob);
friend doublelong operator+(doublelong &ob1, doublelong &ob2);
friend doublelong operator-(doublelong &ob1, doublelong &ob2);
friend doublelong operator*(doublelong &ob1, doublelong &ob2);
friend doublelong operator/(doublelong &ob1, doublelong &ob2);
void operator+=(doublelong &ob);
void operator-=(doublelong &ob);
void operator/=(doublelong &ob);
};
void sub(char str1[], char str2[], char result[])
{
int len1 = strlen(str1);
int len2 = strlen(str2);
if (len1<len2)
{
char temp;
strcpy(temp, str1);
strcpy(str1, str2);
strcpy(str2, temp);
int t = len1;
len1 = len2;
len2 = t;
}
int num1 = { 0 }, num2 = { 0 };
int i;
for (i = 0; i<len1; i++)
{
num1 = str1 - '0';
}
for (i = 0; i<len2; i++)
{
num2 = str2 - '0';
}
for (i = 0; i<len1 / 2; i++)
{
int temp = num1;
num1 = num1;
num1 = temp;
}
for (i = 0; i<len2 / 2; i++)
{
int temp = num2;
num2 = num2;
num2 = temp;
}
int len = len1>len2 ? len1 : len2;
int ans = { 0 };
for (i = 0; i<len; i++)
{
if (num1 - num2<0)
{
ans = num1 + 10 - num2;
num1 -= 1;
}
else
{
ans = num1 - num2;
}
}
for (i = len - 1; i >= 0; i--)
{
if (ans != 0)
break;
}
if (i == -1)
result = '0';
else
{
int j;
if (result != '-')
j = 0;
else
j = 1;
while (i >= 0)
{
result = ans + '0';
j++;
i--;
}
}
}
void add(char str1[], char str2[], char result[])
{
int num1 = { 0 }, num2 = { 0 };
int len1 = strlen(str1);
int len2 = strlen(str2);
int i;
for (i = 0; i<len1; i++)
{
num1 = str1 - '0';
}
for (i = 0; i<len2; i++)
{
num2 = str2 - '0';
}
for (i = 0; i<len1 / 2; i++)
{
int temp = num1;
num1 = num1;
num1 = temp;
}
for (i = 0; i<len2 / 2; i++)
{
int temp = num2;
num2 = num2;
num2 = temp;
}
int len = len1>len2 ? len1 : len2;
int ans = { 0 };
for (i = 0; i<len; i++)
{
ans += num1 + num2;
if (ans >= 10)
{
ans += ans / 10;
ans = ans % 10;
}
}
for (i = len; i >= 0; i--)
{
if (ans != 0)
break;
}
int j;
if (result != '-')
j = 0;
else
j = 1;
while (i >= 0)
{
result = ans + '0';
j++;
i--;
}
}
void multiply(char str1[], char str2[], char result[])
{
int num1 = { 0 };
int num2 = { 0 };
int ans = { 0 };
int len1 = strlen(str1);
int len2 = strlen(str2);
int len = len1>len2 ? len1 : len2;
int i, j;
for (j = 0, i = len1 - 1; i >= 0; i--)
num1 = str1 - '0';
for (j = 0, i = len2 - 1; i >= 0; i--)
num2 = str2 - '0';
for (i = 0; i<len1; i++)
{
for (j = 0; j<len2; j++)
ans = ans + num1 * num2;
}
for (i = 0; i<len * 2; i++)
{
if (ans >= 10)
{
ans = ans + ans / 10;
ans = ans % 10;
}
}
for (i = len * 2; i>0; i--)
{
if (ans != 0)
break;
}
if (result != '-')
j = 0;
else
j = 1;
while (i >= 0)
{
result = ans + '0';
j++;
i--;
}
}
int SubStract(int *p1, int *p2, int len1, int len2)
{
int i;
if (len1<len2)
return -1;
if (len1 == len2)
{
for (i = len1 - 1; i >= 0; i--)
{
if (p1>p2)
break;
else if (p1<p2)
return -1;
}
}
for (i = 0; i <= len1 - 1; i++)
{
p1 -= p2;
if (p1<0)
{
p1 += 10;
p1--;
}
}
for (i = len1 - 1; i >= 0; i--)
if (p1)
return i + 1;
return 0;
}
void division(char str1[], char str2[], char result[])
{
int i, j;
int nTimes;
int nTemp;
int num1 = { 0 };
int num2 = { 0 };
int ans = { 0 };
int len1 = strlen(str1);
int len2 = strlen(str2);
for (j = 0, i = len1 - 1; i >= 0; j++, i--)
num1 = str1 - '0';
for (j = 0, i = len2 - 1; i >= 0; j++, i--)
num2 = str2 - '0';
if (len1<len2)
{
result = '0';
return;
}
nTimes = len1 - len2;
for (i = len1 - 1; i >= 0; i--)
{
if (i >= nTimes)
num2 = num2;
else
num2 = 0;
}
len2 = len1;
for (j = 0; j <= nTimes; j++)
{
while ((nTemp = SubStract(num1, num2 + j, len1, len2 - j)) >= 0)
{
len1 = nTemp;
ans++;
}
}
for (i = 9; i >= 0; i--)
{
if (ans != 0)
break;
}
if (result != '-')
j = 0;
else
j = 1;
while (i >= 0)
{
result = ans + '0';
j++;
i--;
}
}
istream & operator>>(istream &is, doublelong &ob)
{
is >> ob.number;
return is;
}
ostream & operator<<(ostream &os, const doublelong &ob)
{
os << ob.number;
return os;
}
doublelong operator+(doublelong &ob1, doublelong &ob2)
{
char result;
char str1, str2;
strcpy(str1, ob1.number);
strcpy(str2, ob2.number);
if (str1 == '-'&&str2 == '-')
{
result = '-';
add(str1 + 1, str2 + 1, result);
}
else if (str1 == '-'&&str2 != '-')
{
int len1 = strlen(str1 + 1);
int len2 = strlen(str2);
if (len1 == len2)
{
if (strcmp(str1 + 1, str2)>0)
{
result = '-';
sub(str1 + 1, str2, result);
}
else
{
sub(str2, str1 + 1, result);
}
}
else if (len1>len2)
{
result = '-';
sub(str1 + 1, str2, result);
}
else
{
sub(str1 + 1, str2, result);
}
}
else if (str1 != '-'&&str2 == '-')
{
int len1 = strlen(str1);
int len2 = strlen(str2 + 1);
if (len1 == len2)
{
if (strcmp(str1, str2 + 1)>0)
{
sub(str1, str2 + 1, result);
}
else
{
result = '-';
sub(str2 + 1, str1, result);
}
}
else if (len1<len2)
{
result='-';
sub(str1, str2 + 1, result);
}
else
{
sub(str1, str2 + 1, result);
}
}
else if (str1 != '-'&&str2 != '-')
{
add(str1, str2, result);
}
return doublelong(result);
}
doublelong operator-(doublelong &ob1, doublelong &ob2)
{
char result;
char str1, str2;
strcpy(str1, ob1.number);
strcpy(str2, ob2.number);
if (str1 != '-'&&str2 == '-')
{
add(str1, str2 + 1, result);
}
else if (str1 == '-'&&str2 != '-')
{
result = '-';
add(str1 + 1, str2, result);
}
else if (str1 != '-'&&str2 != '-')
{
int len1 = strlen(str1);
int len2 = strlen(str2);
if (len1 == len2)
{
if (strcmp(str1, str2)>0)
{
sub(str1, str2, result);
}
else
{
result = '-';
sub(str2, str1, result);
}
}
else if (len1>len2)
{
sub(str1, str2, result);
}
else
{
result = '-';
sub(str1, str2, result);
}
}
else
{
int len1 = strlen(str1 + 1);
int len2 = strlen(str2 + 1);
if (len1 == len2)
{
if (strcmp(str2 + 1, str1 + 1) >= 0)
{
sub(str2 + 1, str1 + 1, result);
}
else
{
result = '-';
sub(str1 + 1, str2 + 1, result);
}
}
else if (len1>len2)
{
result = '-';
sub(str1 + 1, str2 + 1, result);
}
else
{
sub(str1 + 1, str2 + 1, result);
}
}
return doublelong(result);
}
doublelong operator*(doublelong &ob1, doublelong &ob2)
{
char result;
char str1, str2;
strcpy(str1, ob1.number);
strcpy(str2, ob2.number);
if (strcmp(str1, "0") == 0 || strcmp(str2, "0") == 0)
{
return doublelong("0");
}
if (str1 != '-'&&str2 == '-')
{
result = '-';
multiply(str1, str2 + 1, result);
}
else if (str1 == '-'&&str2 != '-')
{
result = '-';
multiply(str1 + 1, str2, result);
}
else if (str1 == '-'&&str2 == '-')
{
multiply(str1 + 1, str2 + 1, result);
}
else
{
multiply(str1, str2, result);
}
return doublelong(result);
}
doublelong operator/(doublelong &ob1, doublelong &ob2)
{
char result;
char str1, str2;
strcpy(str1, ob1.number);
strcpy(str2, ob2.number);
if (str1 != '-'&&str2 == '-')
{
result = '-';
division(str1, str2 + 1, result);
}
else if (str1 == '-'&&str2 != '-')
{
result = '-';
division(str1 + 1, str2, result);
}
else if (str1 == '-'&&str2 == '-')
{
division(str1 + 1, str2 + 1, result);
}
else
{
division(str1, str2, result);
}
return doublelong(result);
}
void doublelong::operator+=(doublelong &ob)
{
char result;
char str1, str2;
strcpy(str1, this->number);
strcpy(str2, ob.number);
if (str1 == '-'&&str2 == '-')
{
result = '-';
add(str1 + 1, str2 + 1, result);
}
else if (str1 == '-'&&str2 != '-')
{
int len1 = strlen(str1 + 1);
int len2 = strlen(str2);
if (len1 == len2)
{
if (strcmp(str1 + 1, str2)>0)
{
result = '-';
sub(str1 + 1, str2, result);
}
else
{
sub(str2, str1 + 1, result);
}
}
else if (len1>len2)
{
result = '-';
sub(str1 + 1, str2, result);
}
else
{
sub(str1 + 1, str2, result);
}
}
else if (str1 != '-'&&str2 == '-')
{
int len1 = strlen(str1);
int len2 = strlen(str2 + 1);
if (len1 == len2)
{
if (strcmp(str1, str2 + 1)>0)
{
sub(str1, str2 + 1, result);
}
else
{
result = '-';
sub(str2 + 1, str1, result);
}
}
else if (len1<len2)
{
result='-';
sub(str1, str2 + 1, result);
}
else
{
sub(str1, str2 + 1, result);
}
}
else if (str1 != '-'&&str2 != '-')
{
add(str1, str2, result);
}
strcpy(this->number, result);
}
void doublelong::operator-=(doublelong &ob)
{
char result;
char str1, str2;
strcpy(str1, this->number);
strcpy(str2, ob.number);
if (str1 != '-'&&str2 == '-')
{
add(str1, str2 + 1, result);
}
else if (str1 == '-'&&str2 != '-')
{
result = '-';
add(str1 + 1, str2, result);
}
else if (str1 != '-'&&str2 != '-')
{
int len1 = strlen(str1);
int len2 = strlen(str2);
if (len1 == len2)
{
if (strcmp(str1, str2)>0)
{
sub(str1, str2, result);
}
else
{
result = '-';
sub(str2, str1, result);
}
}
else if (len1>len2)
{
sub(str1, str2, result);
}
else
{
result = '-';
sub(str1, str2, result);
}
}
else
{
int len1 = strlen(str1 + 1);
int len2 = strlen(str2 + 1);
if (len1 == len2)
{
if (strcmp(str2 + 1, str1 + 1) >= 0)
{
sub(str2 + 1, str1 + 1, result);
}
else
{
result = '-';
sub(str1 + 1, str2 + 1, result);
}
}
else if (len1>len2)
{
result = '-';
sub(str1 + 1, str2 + 1, result);
}
else
{
sub(str1 + 1, str2 + 1, result);
}
}
strcpy(this->number, result);
}
void doublelong::operator/=(doublelong &ob)
{
char result;
char str1, str2;
strcpy(str1, this->number);
strcpy(str2, ob.number);
if (str1 != '-'&&str2 == '-')
{
result = '-';
division(str1, str2 + 1, result);
}
else if (str1 == '-'&&str2 != '-')
{
result = '-';
division(str1 + 1, str2, result);
}
else if (str1 == '-'&&str2 == '-')
{
division(str1 + 1, str2 + 1, result);
}
else
{
division(str1, str2, result);
}
strcpy(this->number, result);
}
int main()
{
doublelong a = "100", b = "-7", c;
c = a*b;
cout << c << endl;
c = "0";
cout << c << endl;
return 0;
}

TCY 发表于 2019-1-3 13:25:22

本帖最后由 TCY 于 2019-1-3 13:26 编辑

用代码格式：
#include<iostream>
#include<cstring>
#define MAX 65*65
using namespace std;
class doublelong{
   char number;
public:
   doublelong(const char *str = " ")
   {
            strcpy(number, str);
   }
   void show()
   {
            cout << number << endl;
   }
   void operator>>(doublelong a)
   {
            cin >> number;
   }
   friend istream & operator>>(istream &is, doublelong &ob);
   friend ostream & operator<<(ostream &os, const doublelong &ob);
   friend doublelong operator+(doublelong &ob1, doublelong &ob2);
   friend doublelong operator-(doublelong &ob1, doublelong &ob2);
   friend doublelong operator*(doublelong &ob1, doublelong &ob2);
   friend doublelong operator/(doublelong &ob1, doublelong &ob2);
   void operator+=(doublelong &ob);
   void operator-=(doublelong &ob);
   void operator/=(doublelong &ob);
};
void sub(char str1[], char str2[], char result[])
{
   int len1 = strlen(str1);
   int len2 = strlen(str2);
   if (len1<len2)
   {
            char temp;
            strcpy(temp, str1);
            strcpy(str1, str2);
            strcpy(str2, temp);
            int t = len1;
            len1 = len2;
            len2 = t;
   }
   int num1 = { 0 }, num2 = { 0 };
   int i;
   for (i = 0; i<len1; i++)
   {
            num1 = str1 - '0';
   }
   for (i = 0; i<len2; i++)
   {
            num2 = str2 - '0';
   }
   for (i = 0; i<len1 / 2; i++)
   {
            int temp = num1;
            num1 = num1;
            num1 = temp;
   }
   for (i = 0; i<len2 / 2; i++)
   {
            int temp = num2;
            num2 = num2;
            num2 = temp;
   }
   int len = len1>len2 ? len1 : len2;
   int ans = { 0 };
   for (i = 0; i<len; i++)
   {
            if (num1 - num2<0)
            {
                     ans = num1 + 10 - num2;
                     num1 -= 1;
            }
            else
            {
                     ans = num1 - num2;
            }
   }
   for (i = len - 1; i >= 0; i--)
   {
            if (ans != 0)
                     break;
   }
   if (i == -1)
            result = '0';
   else
   {
            int j;
            if (result != '-')
                     j = 0;
            else
                     j = 1;
            while (i >= 0)
            {
                     result = ans + '0';
                     j++;
                     i--;
            }
   }
}
void add(char str1[], char str2[], char result[])
{
   int num1 = { 0 }, num2 = { 0 };
   int len1 = strlen(str1);
   int len2 = strlen(str2);
   int i;
   for (i = 0; i<len1; i++)
   {
            num1 = str1 - '0';
   }
   for (i = 0; i<len2; i++)
   {
            num2 = str2 - '0';
   }
   for (i = 0; i<len1 / 2; i++)
   {
            int temp = num1;
            num1 = num1;
            num1 = temp;
   }
   for (i = 0; i<len2 / 2; i++)
   {
            int temp = num2;
            num2 = num2;
            num2 = temp;
   }
   int len = len1>len2 ? len1 : len2;
   int ans = { 0 };
   for (i = 0; i<len; i++)
   {
            ans += num1 + num2;
            if (ans >= 10)
            {
                     ans += ans / 10;
                     ans = ans % 10;
            }
   }
   for (i = len; i >= 0; i--)
   {
            if (ans != 0)
                     break;
   }
   int j;
   if (result != '-')
            j = 0;
   else
            j = 1;
   while (i >= 0)
   {
            result = ans + '0';
            j++;
            i--;
   }
}
void multiply(char str1[], char str2[], char result[])
{
   int num1 = { 0 };
   int num2 = { 0 };
   int ans = { 0 };
   int len1 = strlen(str1);
   int len2 = strlen(str2);
   int len = len1>len2 ? len1 : len2;
   int i, j;
   for (j = 0, i = len1 - 1; i >= 0; i--)
            num1 = str1 - '0';
   for (j = 0, i = len2 - 1; i >= 0; i--)
            num2 = str2 - '0';
   for (i = 0; i<len1; i++)
   {
            for (j = 0; j<len2; j++)
                     ans = ans + num1 * num2;
   }
   for (i = 0; i<len * 2; i++)
   {
            if (ans >= 10)
            {
                     ans = ans + ans / 10;
                     ans = ans % 10;
            }
   }
   for (i = len * 2; i>0; i--)
   {
            if (ans != 0)
                     break;
   }
   if (result != '-')
            j = 0;
   else
            j = 1;
   while (i >= 0)
   {
            result = ans + '0';
            j++;
            i--;
   }
}
int SubStract(int *p1, int *p2, int len1, int len2)
{
   int i;
   if (len1<len2)
            return -1;
   if (len1 == len2)
   {
            for (i = len1 - 1; i >= 0; i--)
            {
                     if (p1>p2)
                           break;
                     else if (p1<p2)
                           return -1;
            }
   }
   for (i = 0; i <= len1 - 1; i++)
   {
            p1 -= p2;
            if (p1<0)
            {
                     p1 += 10;
                     p1--;
            }
   }
   for (i = len1 - 1; i >= 0; i--)
            if (p1)
                     return i + 1;
   return 0;
}
void division(char str1[], char str2[], char result[])
{
   int i, j;
   int nTimes;
   int nTemp;
   int num1 = { 0 };
   int num2 = { 0 };
   int ans = { 0 };
   int len1 = strlen(str1);
   int len2 = strlen(str2);
   for (j = 0, i = len1 - 1; i >= 0; j++, i--)
            num1 = str1 - '0';
   for (j = 0, i = len2 - 1; i >= 0; j++, i--)
            num2 = str2 - '0';
   if (len1<len2)
   {
            result = '0';
            return;
   }
   nTimes = len1 - len2;
   for (i = len1 - 1; i >= 0; i--)
   {
            if (i >= nTimes)
                     num2 = num2;
            else
                     num2 = 0;
   }
   len2 = len1;
   for (j = 0; j <= nTimes; j++)
   {
            while ((nTemp = SubStract(num1, num2 + j, len1, len2 - j)) >= 0)
            {
                     len1 = nTemp;
                     ans++;
            }
   }
   for (i = 9; i >= 0; i--)
   {
            if (ans != 0)
                     break;
   }
   if (result != '-')
            j = 0;
   else
            j = 1;
   while (i >= 0)
   {
            result = ans + '0';
            j++;
            i--;
   }
}
istream & operator>>(istream &is, doublelong &ob)
{
   is >> ob.number;
   return is;
}
ostream & operator<<(ostream &os, const doublelong &ob)
{
   os << ob.number;
   return os;
}
doublelong operator+(doublelong &ob1, doublelong &ob2)
{
   char result;
   char str1, str2;
   strcpy(str1, ob1.number);
   strcpy(str2, ob2.number);
   if (str1 == '-'&&str2 == '-')
   {
            result = '-';
            add(str1 + 1, str2 + 1, result);
   }
   else if (str1 == '-'&&str2 != '-')
   {
            int len1 = strlen(str1 + 1);
            int len2 = strlen(str2);
            if (len1 == len2)
            {
                     if (strcmp(str1 + 1, str2)>0)
                     {
                           result = '-';
                           sub(str1 + 1, str2, result);
                     }
                     else
                     {
                           sub(str2, str1 + 1, result);
                     }
            }
            else if (len1>len2)
            {
                     result = '-';
                     sub(str1 + 1, str2, result);
            }
            else
            {
                     sub(str1 + 1, str2, result);
            }
   }
   else if (str1 != '-'&&str2 == '-')
   {
            int len1 = strlen(str1);
            int len2 = strlen(str2 + 1);
            if (len1 == len2)
            {
                     if (strcmp(str1, str2 + 1)>0)
                     {
                           sub(str1, str2 + 1, result);
                     }
                     else
                     {
                           result = '-';
                           sub(str2 + 1, str1, result);
                     }
            }
            else if (len1<len2)
            {
                     result='-';
                     sub(str1, str2 + 1, result);
            }
            else
            {
                     sub(str1, str2 + 1, result);
            }
   }
   else if (str1 != '-'&&str2 != '-')
   {
            add(str1, str2, result);
   }
   return doublelong(result);
}
doublelong operator-(doublelong &ob1, doublelong &ob2)
{
   char result;
   char str1, str2;
   strcpy(str1, ob1.number);
   strcpy(str2, ob2.number);
   if (str1 != '-'&&str2 == '-')
   {
            add(str1, str2 + 1, result);
   }
   else if (str1 == '-'&&str2 != '-')
   {
            result = '-';
            add(str1 + 1, str2, result);
   }
   else if (str1 != '-'&&str2 != '-')
   {
            int len1 = strlen(str1);
            int len2 = strlen(str2);
            if (len1 == len2)
            {
                     if (strcmp(str1, str2)>0)
                     {
                           sub(str1, str2, result);
                     }
                     else
                     {
                           result = '-';
                           sub(str2, str1, result);
                     }
            }
            else if (len1>len2)
            {
                     sub(str1, str2, result);
            }
            else
            {
                     result = '-';
                     sub(str1, str2, result);
            }
   }
   else
   {
            int len1 = strlen(str1 + 1);
            int len2 = strlen(str2 + 1);
            if (len1 == len2)
            {
                     if (strcmp(str2 + 1, str1 + 1) >= 0)
                     {
                           sub(str2 + 1, str1 + 1, result);
                     }
                     else
                     {
                           result = '-';
                           sub(str1 + 1, str2 + 1, result);
                     }
            }
            else if (len1>len2)
            {
                     result = '-';
                     sub(str1 + 1, str2 + 1, result);
            }
            else
            {
                     sub(str1 + 1, str2 + 1, result);
            }
   }
   return doublelong(result);
}
doublelong operator*(doublelong &ob1, doublelong &ob2)
{
   char result;
   char str1, str2;
   strcpy(str1, ob1.number);
   strcpy(str2, ob2.number);
   if (strcmp(str1, "0") == 0 || strcmp(str2, "0") == 0)
   {
            return doublelong("0");
   }
   if (str1 != '-'&&str2 == '-')
   {
            result = '-';
            multiply(str1, str2 + 1, result);
   }
   else if (str1 == '-'&&str2 != '-')
   {
            result = '-';
            multiply(str1 + 1, str2, result);
   }
   else if (str1 == '-'&&str2 == '-')
   {
            multiply(str1 + 1, str2 + 1, result);
   }
   else
   {
            multiply(str1, str2, result);
   }
   return doublelong(result);
}
doublelong operator/(doublelong &ob1, doublelong &ob2)
{
   char result;
   char str1, str2;
   strcpy(str1, ob1.number);
   strcpy(str2, ob2.number);
   if (str1 != '-'&&str2 == '-')
   {
            result = '-';
            division(str1, str2 + 1, result);
   }
   else if (str1 == '-'&&str2 != '-')
   {
            result = '-';
            division(str1 + 1, str2, result);
   }
   else if (str1 == '-'&&str2 == '-')
   {
            division(str1 + 1, str2 + 1, result);
   }
   else
   {
            division(str1, str2, result);
   }
   return doublelong(result);
}
void doublelong::operator+=(doublelong &ob)
{
   char result;
   char str1, str2;
   strcpy(str1, this->number);
   strcpy(str2, ob.number);
   if (str1 == '-'&&str2 == '-')
   {
            result = '-';
            add(str1 + 1, str2 + 1, result);
   }
   else if (str1 == '-'&&str2 != '-')
   {
            int len1 = strlen(str1 + 1);
            int len2 = strlen(str2);
            if (len1 == len2)
            {
                     if (strcmp(str1 + 1, str2)>0)
                     {
                           result = '-';
                           sub(str1 + 1, str2, result);
                     }
                     else
                     {
                           sub(str2, str1 + 1, result);
                     }
            }
            else if (len1>len2)
            {
                     result = '-';
                     sub(str1 + 1, str2, result);
            }
            else
            {
                     sub(str1 + 1, str2, result);
            }
   }
   else if (str1 != '-'&&str2 == '-')
   {
            int len1 = strlen(str1);
            int len2 = strlen(str2 + 1);
            if (len1 == len2)
            {
                     if (strcmp(str1, str2 + 1)>0)
                     {
                           sub(str1, str2 + 1, result);
                     }
                     else
                     {
                           result = '-';
                           sub(str2 + 1, str1, result);
                     }
            }
            else if (len1<len2)
            {
                     result='-';
                     sub(str1, str2 + 1, result);
            }
            else
            {
                     sub(str1, str2 + 1, result);
            }
   }
   else if (str1 != '-'&&str2 != '-')
   {
            add(str1, str2, result);
   }
   strcpy(this->number, result);
}
void doublelong::operator-=(doublelong &ob)
{
   char result;
   char str1, str2;
   strcpy(str1, this->number);
   strcpy(str2, ob.number);
   if (str1 != '-'&&str2 == '-')
   {
            add(str1, str2 + 1, result);
   }
   else if (str1 == '-'&&str2 != '-')
   {
            result = '-';
            add(str1 + 1, str2, result);
   }
   else if (str1 != '-'&&str2 != '-')
   {
            int len1 = strlen(str1);
            int len2 = strlen(str2);
            if (len1 == len2)
            {
                     if (strcmp(str1, str2)>0)
                     {
                           sub(str1, str2, result);
                     }
                     else
                     {
                           result = '-';
                           sub(str2, str1, result);
                     }
            }
            else if (len1>len2)
            {
                     sub(str1, str2, result);
            }
            else
            {
                     result = '-';
                     sub(str1, str2, result);
            }
   }
   else
   {
            int len1 = strlen(str1 + 1);
            int len2 = strlen(str2 + 1);
            if (len1 == len2)
            {
                     if (strcmp(str2 + 1, str1 + 1) >= 0)
                     {
                           sub(str2 + 1, str1 + 1, result);
                     }
                     else
                     {
                           result = '-';
                           sub(str1 + 1, str2 + 1, result);
                     }
            }
            else if (len1>len2)
            {
                     result = '-';
                     sub(str1 + 1, str2 + 1, result);
            }
            else
            {
                     sub(str1 + 1, str2 + 1, result);
            }
   }
   strcpy(this->number, result);
}
void doublelong::operator/=(doublelong &ob)
{
   char result;
   char str1, str2;
   strcpy(str1, this->number);
   strcpy(str2, ob.number);
   if (str1 != '-'&&str2 == '-')
   {
            result = '-';
            division(str1, str2 + 1, result);
   }
   else if (str1 == '-'&&str2 != '-')
   {
            result = '-';
            division(str1 + 1, str2, result);
   }
   else if (str1 == '-'&&str2 == '-')
   {
            division(str1 + 1, str2 + 1, result);
   }
   else
   {
            division(str1, str2, result);
   }
   strcpy(this->number, result);
}
int main()
{
   doublelong a = "100", b = "-7", c;
   c = a*b;
   cout << c << endl;
   c = "0";
   cout << c << endl;
   return 0;
}
这个应该是把字符串变成数字运算

天涯忘 发表于 2019-1-3 13:52:30

TCY 发表于 2019-1-3 13:25
用代码格式：

这个应该是把字符串变成数字运算

我想知道四则运算的算法具体每一步是啥意思，能否注释一下？

DAY 发表于 2019-1-3 18:29:10

写代码的应该该批，这么长的代码一点注释都没有，

页: [1]

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超长整数类