c++中strsub()的用法

首先声明我的确时一个新手，一个substr（）函数让我的一个项目功能出现了问题。

先给一下msdn上的内容要求吧。

其功能是 Copies a substring of at most some number of characters from a string beginning from a specified position.

内部定义的函数是：

basic_string substr(   size_type _Off = 0,   size_type _Count = npos) const;

 

解释一下参数吧，这里有两个参数，第一个参数是要截取的字符串的起始位置，后一个参数是要截取字符串的长度。

返回值：Return Value

A substring object that is a copy of elements of the string operand beginning at the position specified by the first argument.

例子：

// basic_string_substr.cpp// compile with: /EHsc#include <string>#include <iostream>int main( ) {   using namespace std;   string  str1 ("Heterological paradoxes are persistent.");   cout << "The original string str1 is: \n " << str1        << endl << endl;   basic_string <char> str2 = str1.substr ( 6 , 7 );   cout << "The substring str1 copied is: " << str2        << endl << endl;      basic_string <char> str3 = str1.substr (  );   cout << "The default substring str3 is: \n " << str3        <<  "\n which is the entire original string." << endl;}

 

输出结果是

The original string str1 is:  Heterological paradoxes are persistent.

The substring str1 copied is: logicalThe default substring str3 is:  Heterological paradoxes are persistent. 

which is the entire original string.