C++黑马程序员——P193-196. string容器 字符串比较,字符存取,字符串插入和删除,子串获取

 1 //字符串比较
 2 void test01() {
 3     string str1 = "hello";
 4     string str2 = "hello";
 5     if (str1.compare(str2) == 0) {
 6         cout << "str1 == str2" << endl;
 7     }
 8 }
 9 
10 int main() {
11     test01();
12     return 0;
13 }

 1 int main() {
 2     string str = "hello";
 3 
 4     for (int i = 0; i < str.size(); i++) {
 5         cout << str[i] << " ";
 6     }
 7     cout << endl;
 8 
 9     for (int i = 0; i < str.size(); i++) {
10         cout << str.at(i) << " ";
11     }
12     cout << endl;
13 
14     return 0;
15 }

1 int main() {
2     string str = "hello";
3     string str1 = str.substr(1, 3);    //str1 = "ell"
4     cout << str1 << endl;
5     return 0;
6 }