C++中substr函数的用法

int main(){string str1("Heterological paradoxes are persistent.");cout << "str1 is:" << endl;cout << str1 << endl;basic_string<char>str2 = str1.substr(6, 7);cout << "str2  is:" << str2 << endl;basic_string<char>str3 = str1.substr();cout << "str3 is:" << endl;cout << str3 << endl;basic_string<char>str4 = str1.substr(6);cout << "str4 is:" << endl;cout << str4 << endl;return 0;}

结果是

 

str1.substr(6, 7)

<span style="font-family: Arial; background-color: rgb(255, 255, 255);">str1.substr(6,7)获得字符串str1中 从第6位开始的长度为7的字符串,</span>

str3 = str1.substr();//<span style="font-family: Arial; font-size: 14px; line-height: 26px; background-color: rgb(255, 255, 255);">而 默认时的长度为从开始位置到尾</span>

str4 = str1.substr(6);//获得从该位置开始的字符串