c++ “=” 重载
本帖最后由 kkk222 于 2019-6-8 12:07 编辑[*]#include <iostream>
[*]#include <cstring>
[*]using namespace std;
[*]class Complex
[*]{
[*]private:
[*] double r, i;
[*]public:
[*] void Print()
[*] {
[*] cout << r << "+" << i << "i" << endl;
[*] }
[*] Complex operator =(const string& s);
[*]};
[*]Complex Complex::operator =(const string& s)
[*]{
[*] Complex temp;
[*] int pos = s.find("+",0);
[*] string sTmp = s.substr(0, pos);
[*] temp.r = atof(sTmp.c_str());
[*] sTmp = s.substr(pos + 1, s.length() - pos - 2);
[*] temp.i = atof(sTmp.c_str());
[*] cout << temp.r << "+" << temp.i << "i" << endl;
[*] return temp;
[*]}
[*]int main()
[*]{
[*] Complex a;
[*] a = "3+4i"; a.Print();
[*] a = "5+6i"; a.Print();
[*] return 0;
[*]}
程序的目的是把字符串中“+”前面的数赋值给对象的实部，“+”后面到“i”前面的数赋值给虚部
程序的结果：
对象a的实部和虚部怎么都是指数？
为啥我编译不通过?
hello.cpp: In member function ‘Complex Complex::operator=(const string&)’:
hello.cpp:20:35: error: ‘atof’ was not declared in this scope
temp.r = atof(sTmp.c_str());
^
#include <iostream>
#include <cstring>
#include <cstdlib>
#include <string>
using namespace std;
class Complex
{
private:
double r, i;
public:
void Print()
{
cout << r << "+" << i << "i" << endl;
}
Complex & operator =(const string& s);
};
Complex & Complex::operator =(const string& s)
{
Complex temp;
int pos = s.find("+",0);
string sTmp = s.substr(0, pos);
temp.r = atof(sTmp.c_str());
sTmp = s.substr(pos + 1, s.length() - pos - 2);
temp.i = atof(sTmp.c_str());
cout << temp.r << "+" << temp.i << "i" << endl;
this->r = temp.r;
this->i = temp.i;
return *this;
}
int main()
{
Complex a;
a = "3+4i"; a.Print();
a = "5+6i"; a.Print();
return 0;
}
返回引用
鸣人不说暗话，我要最佳答案！！！ 我就是个弟弟 发表于 2019-6-8 20:12
返回引用
鸣人不说暗话，我要最佳答案！！！
16行代码那里Complex & operator 的‘&’是引用吗？
为什么要返回 *this 而不能返回temp？ kkk222 发表于 2019-6-9 14:38
16行代码那里Complex & operator 的‘&’是引用吗？
为什么要返回 *this 而不能返回temp？
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