万行代码计划 Day05
万行代码计划Day05，50行
进度300/10000
有兴趣的伙伴可以一起来，互相监督
/*
0730
list 双向串列
不支持随之访问
插入删除元素很快，不会造成迭代器失效
*/
#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include <string>
#include <stdexcept>
/*
string和c-style字符串转换
*/
void func(string s) {
cout << s << endl;
}
void func2(const char *s){
cout << s << endl;
}
void test07(){
string s = "abc";
const char *p = s.c_str();
func(p);//const char * 隐式类型转换为 string
string s2(p);
//func2(s2);//不存在从 "std::string" 到 "const char *" 的适当转换函数
func(s2);
}
void test08()
{
string s = "abcdefg";
char& a = s;
char& b = s;
a = '1';//会改变s的值
b = '2';
cout << s << endl;
cout << (int*)s.c_str() << endl;
s = "pppppppppppppp";
//a = '1';
//b = '2';
cout << s << endl;
cout << (int*)s.c_str() << endl;//地址指向“ppppppppp”
}
/*
string插入和删除操作
string& insert(int pos, const char* s); //插入字符串
string& insert(int pos, const string& str); //插入字符串
string& insert(int pos, int n, char c);//在指定位置插入n个字符c
string& erase(int pos, int n = npos);//删除从Pos开始的n个字符
*/
void test06(){
string s1("hello");
s1.insert(1,"111");
cout << s1 << endl;
s1.insert(1,s1);
cout << s1 << endl;
//删除
s1.erase(1,3);
cout << s1 << endl;
}
/*
string子串
string substr(int pos = 0, int n = npos) const;//返回由pos开始的n个字符组成的字符串
*/
//需求查找一个右键的 用户名
void test05()
{
string email = "zhangsan@qq.com";
auto pos = email.find('@');
cout << "pos @ = " << pos << endl;
auto usrName = email.substr(0,pos);
cout << "用户名为：" << usrName << endl;
}
/*
string存取字符操作
char& operator[](int n);//通过[]方式取字符
char& at(int n);//通过at方法获取字符
*/
void test02()
{
string s = "hello world";
for (int i = 0; i < s.size();i++)
{
//cout << s << endl;
cout << s.at(i) << endl;
}
//[] 和at区别？[]访问越界直接挂掉 at会抛出异常
try
{
cout << s << endl;
cout << "s" << endl;
cout << s.at(100) << endl;
}
catch (out_of_range & e)
{
cout << e.what() << endl;
cout << "s.at(100) error" << endl;
}
catch (...)
{
cout << "越界异常" << endl;
}
}
int main()
{
test07();
test08();
test06();
test05();
test02();
}
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