C++ string容器 赋值操作 与 字符串拼接

#include <iostream>
using namespace std;

/*
string& operator+=(const char* str);   //重载+=操作符
string& operator+=(const char c);   //重载+=操作符
string& operator+=(const string& str);   //重载+=操作符
string& append(const char* s);        //把字符串s连接到当前字符串结尾
string& append(const char* s，int n); //把字符串s的前n个字符连接到当前字符串结尾
string& append(const string& s);      //同operator+=(const string& str)
string& append(const string& s,int pos,int n);//字符串s中从pos开始的n个字符

*/

void test01()
{
    string str1 = "我";
    str1 += "爱玩游戏";
    cout << "str1 = " << str1 << endl;

    str1 += ':';
    cout << "str1 = " << str1 << endl;

    string str2 = "LOL DNF";
    str1 += str2;
    cout << "str1 = " << str1 << endl;

    string str3 = "I";
    str3.append(" love ");
    cout << "str3 = " << str3 << endl;
    
    str3.append("game:abcde", 5);
    //I love game:
    cout << "str3 = " << str3 << endl;
    
    //str3.append(str2);
    
    //str3.append(str2, 0, 3);//只截取到LOL
    //I love game:LOL

    str3.append(str2, 4, 3);//只截取DNF 参数2表示从哪个位置开始截取 参数3表示截取字符的个数
    cout << "str3 = " << str3 << endl;
}

int main()
{
    test01();

    system("pause");
    return 0;
}

 

#include <iostream>
using namespace std;

/*
- string& operator=(const char* s);    //char*类型字符串 赋值给当前的字符串
- string& operator=(const string &s);  //把字符串s赋值给当前的字符串
- string& operator=(char* c);          //字符赋值给当前的字符串
- string& assign(const char* s);       //把字符串s赋值给当前的字符串
- string& assign(const char* s,int n);  //把字符串s的前n个字符赋给当前字符串
- string& assign(const string& s);        //把字符串s赋值给当前字符串
- string& assign(int n,char c);            //用n个字符c赋给当前字符串
*/

void test01()
{
    string str1;
    str1 = "hello world";
    cout << "str1 = " << str1 << endl;

    string str2;
    str2 = str1;
    cout << "str2 = " << str2 << endl;

    string str3;
    str3 = 'a';
    cout << "str3 = " << str3 << endl;

    string str4;
    str4.assign("hello C++");
    cout << "str4 = " << str4 << endl;

    string str5;
    str5.assign("hello C++",5);
    cout << "str5 = " << str5 << endl;

    string str6;
    str6.assign(str5);
    cout << "str6 = " << str6 << endl;

    string str7;
    str7.assign(10,'b');
    cout << "str7 = " << str7 << endl;
}

int main()
{
    test01();

    system("pause");
    return 0;
}