C++字符串string类常用操作详解(一)【初始化、遍历、连接】

代码示例：

#include <iostream>
#include "string"

using namespace std;

//字符串初始化
void strInit()
{
    cout << "字符串初始化:"  <<endl;

    string s1 = "abcdefg";  //初始化方式1
    string s2("abcdefg");   //初始化方式2
    string s3 = s2;         //通过拷贝构造函数 初始化s3
    string s4(7,'s');       //初始化7个s的字符串

    cout << "s1 = "<< s1 << endl;
    cout << "s2 = "<< s2 << endl;
    cout << "s3 = "<< s3 << endl;
    cout << "s4 = "<< s4 << endl;
}

//字符串遍历
void strErgo()
{
    cout << "字符串遍历:"  <<endl;

    string s1 = "abcdefg";  //初始化字符串

    //通过数组方式遍历
    cout << "1、通过数组方式遍历:"  <<endl;
    for (int i = 0; i < s1.length(); i++)
    {
        cout << s1[i] << " ";
    }
    cout << endl;

    //通过迭代器遍历
    cout << "2、通过迭代器遍历:"  <<endl;
    for(string::iterator it = s1.begin(); it!= s1.end(); it++)
    {
        cout << *it << " ";
    }
    cout << endl;

    //通过at()方式遍历
    cout << "3、通过at()方式遍历:"  <<endl;
    for (int i = 0; i < s1.length(); i++)
    {
        cout << s1.at(i) << " ";        //此方式可以在越界时抛出异常
    }
    cout << endl;
}

//字符指针和字符串的转换
void strConvert()
{
    cout << "字符指针和字符串的转换:"  <<endl;
    string s1 = "abcdefg";  //初始化字符串

    cout << "string转换为char*:"  <<endl;
    //string转换为char*
    cout << s1.c_str() <<endl;  //s1.c_str()即为s1的char *形式

    cout << "char*获取string内容:"  <<endl;
    //char*获取string内容
    char buf[64] = {0};
    s1.copy(buf, 7);//复制7个元素
    cout << buf <<endl;
}

//字符串连接
void strAdd()
{
    cout << "字符串连接:"  <<endl;

    cout << "方式1:"  <<endl;
    string s1 = "123";
    string s2 = "456";
    s1 += s2;
    cout << "s1 = "<< s1 << endl;

    cout << "方式2:"  <<endl;
    string s3 = "123";
    string s4 = "456";
    s3.append(s4);
    cout << "s3 = "<< s3 << endl;
}
int main()
{
    //初始化
    strInit();
    cout << endl;
    //遍历
    strErgo();
    cout << endl;
    //字符指针类型和字符串转换
    strConvert();
    cout << endl;
    //字符串连接
    strAdd();
    cout << endl;
    system("pause");
    return 0;
}

程序运行结果：

字符串初始化:
s1 = abcdefg
s2 = abcdefg
s3 = abcdefg
s4 = sssssss

字符串遍历:
1、通过数组方式遍历:
a b c d e f g
2、通过迭代器遍历:
a b c d e f g
3、通过at()方式遍历:
a b c d e f g

字符指针和字符串的转换:
string转换为char*:
abcdefg
char*获取string内容:
abcdefg

字符串连接:
方式1:
s1 = 123456
方式2:
s3 = 123456

请按任意键继续. . .