C++ wmemchr()用法及代碼示例

C /C++中的wmemchr()函數在寬字符塊中定位字符。此函數在ptr指向的塊的前num個字符內搜索ch的首次出現，並返回指向它的指針。

用法:

const wchar_t* wmemchr( const wchar_t* ptr, wchar_t ch, size_t num )
or
wchar_t* wmemchr( wchar_t* ptr, wchar_t ch, size_t num )

參數：該函數接受三個強製性參數，如下所述：

ptr: 指定指向要搜索的字符數組的指針。
ch: 指定要定位的字符。
num: 指定要比較的wchar_t類型的元素數。

返回值：該函數返回兩個值，如下所示：

成功時，它將返回一個指向字符數組位置的指針。
否則，返回NULL指針。

以下示例程序旨在說明上述函數：
程序1：

// C++ program to illustarte 
// wmemchr() function 
  
#include <bits/stdc++.h> 
using namespace std; 
  
int main() 
{ 
    // initialize the string to be scanned 
    wchar_t ptr[] = L"GeeksForGeeks"; 
  
    // character to be searched for 
    wchar_t ch = L'o'; 
  
    // length, till the character to be search for is 8 
    // run the function to check if the character is present 
    bool look = wmemchr(ptr, ch, 8); 
    if (look) 
        wcout << "'" << ch << "'" << L" is present in first "
              << 8 << L" characters of \"" << ptr << "\""; 
    else
        wcout << "'" << ch << "'" << L" is not present in first "
              << 8 << L" characters of \"" << ptr << "\""; 
  
    return 0; 
}

輸出：

'o' is present in first 8 characters of "GeeksForGeeks"

示例2:

// C++ program to illustarte 
// wmemchr() function 
  
#include <bits/stdc++.h> 
using namespace std; 
  
int main() 
{ 
    // initialize the string to be scanned 
    wchar_t ptr[] = L"GFG"; 
  
    // character to be searched for 
    wchar_t ch = L'p'; 
  
    // length, till the character to be search for is 3 
    // run the function to check if the character is present 
    bool look = wmemchr(ptr, ch, 3); 
    if (look) 
        wcout << "'" << ch << "'" << L" is present in first "
              << 3 << L" characters of \"" << ptr << "\""; 
    else
        wcout << "'" << ch << "'" << L" is not present in first "
              << 3 << L" characters of \"" << ptr << "\""; 
  
    return 0; 
}

輸出：

'p' is not present in first 3 characters of "GFG"

相關用法

注：本文由純淨天空篩選整理自AmanSrivastava1大神的英文原創作品 wmemchr() function in C/C++。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。