size and resize (STL Sample)_resize 与 sample-优快云博客

本文介绍如何使用 C++ STL 中的基本字符串方法 size 和 resize。size 方法返回字符串长度，resize 方法用于改变字符串长度，如果字符串变长，则用指定字符填充。示例代码展示了如何使用这些方法。

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basic_string size and resize (STL Sample)
The sample code below illustrates how to use the basic_string size and resize STL functions in Visual C++.
Required Header:<string>
Prototype:
size_type size() const;

void resize(size_type n, E c = E());

resize is defined in header xstring which is included indirectly.

Note: The class/parameter names in the prototype do not match the version in the header file. Some have been modified to improve readability.
Description:The size function returns the length of the sequence. The resize function changes the size to the length specified by the first parameter. If the sequence is made longer, the function appends elements with the value of the second parameter. This value defaults to a null. The output of the sample code shows spaces for the null characters. operator<< reads the size of string and outputs each character in the string one at a time.
Sample Code:
//
//
// Compile options needed: /GX
//
// <filename> : size.cpp
//
// Functions:
//
// size()
// resize() ; Defined in header xstring which is included indirectly.
//

/* Compile options needed: /GX
*/
#include <iostream>
#include <string>

using namespace std;

void main()
{
string TestString = "1111122222333334444455555";
cout << TestString << "/n size: " << TestString.size() << endl;
TestString.resize(5);
cout << TestString << "/n size: " << TestString.size() << endl;
TestString.resize(10);
cout << TestString << "/n size: " << TestString.size() << endl;
TestString.resize(15,'6');
cout << TestString << "/n size: " << TestString.size() << endl;
}

Program Output is:
1111122222333334444455555
size: 25
11111
size: 5
11111
size: 10
11111 66666
size: 15