basic_string定义的相关string函数

std::basic_string::substr

函数定义及功能描述

注: 默认参数npos means "until the end of the string"

示例程序

#include<iostream>
#include <string>

using namespace std;

int main()
{
    string t = "15:30:28";
    
    // 1 5 : 3 0 : 2 8
    // 0 1 2 3 4 5 6 7
    
    string h = t.substr(0, 2);
    string m = t.substr(3, 2);
    string s = t.substr(6);

    cout << h << ' ' << m << ' ' << s << endl;

    return 0;
}

std::basic_string::find

函数定义及功能描述

注:

1. When pos is specified, the search only includes characters at or after position pos，注意当提供pos参数时，是包含pos那个位置的
2. 可以 Find position of a character 也可以 Find position of a C string.
3. If not found, returns npos，即-1

实例程序

#include<iostream>
#include <string>

using namespace std;

int main()
{
    string t = "15:30:28";

    // 1 5 : 3 0 : 2 8
    // 0 1 2 3 4 5 6 7
    
    int pos1 = t.find(':');
    int pos2 = t.find(':', pos1 + 1);

    cout << pos1 << ' ' << pos2 << endl;

    return 0;
}

std::basic_string::rfind

函数定义及功能描述

注:

1. When pos is specified, the search only includes sequences of characters that begin at or before position pos, rfind是倒着找，仅考虑pos及以前的位置
2. 可以 Find position of a character 也可以 Find position of a C string.
3. If not found, returns npos，即-1

实例程序

#include<iostream>
#include <string>

using namespace std;

int main()
{
    string t = "15:30:28";

    // 1 5 : 3 0 : 2 8
    // 0 1 2 3 4 5 6 7

    int pos1 = t.rfind(':');
    int pos2 = t.rfind(':', pos1 - 1);

    cout << pos1 << ' ' << pos2 << endl;

    return 0;
}