wmemset() in C/C++ with Examples

Difficulty Level : Basic
Last Updated : 12 Sep, 2018

The wmemset() function is a builtin function in C/C++ which copies a single wide character for a specified number of time to a wide character array. It is defined within the cwchar header file in C++.

Syntax:

wmemset(des, ch, count)

Parameters: The function accepts three parameters which are described below.

des: It specifies to the wide character array to copy the wide character.
ch: It specifies to the wide character to copy.
count: It specifies to number of times to copy.

Return Value: The function returns three values as follows:

If the count is greater then 0, then function returns des.
If count is less than 0, Segmentation Fault may occur.
If count is equal to zero, the function does nothing.

Below programs illustrate the above function.
Program 1:

// C++ program to illustrate the 
// wmemset() function when count is greater than 0 
#include <cwchar> 
#include <iostream> 
using namespace std; 
  
int main() 
{ 
    wchar_t ch = L'G'; 
    wchar_t des[20]; 
    int count = 10; 
  
    wmemset(des, ch, count); 
    wcout << L"After copying " << ch << L" 10 times" << endl; 
  
    for (int i = 0; i < count; i++) 
        putwchar(des[i]); 
  
    return 0; 
} 

Output:

After copying G 10 times
GGGGGGGGGG

Program 2:

// C++ program to illustrate the 
// wmemset() function when count is 0 
#include <cwchar> 
#include <iostream> 
using namespace std; 
  
int main() 
{ 
    wchar_t ch = L'r'; 
    wchar_t des[20]; 
    int count = 0; 
  
    wmemset(des, ch, count); 
    wcout << L"After copying " << ch << L" 0 times" << endl; 
  
    for (int i = 0; i < count; i++) 
        putwchar(des[i]); 
  
    return 0; 
} 

Output:

After copying r 0 times

Program 3:

// C++ program to illustrate the 
// wmemset() function when  
// count is less than 0 
// returns a segmentation fault  
#include <cwchar> 
#include <iostream> 
using namespace std; 
  
int main() 
{ 
    wchar_t ch = L'q'; 
    wchar_t des[20]; 
    int count = -4; 
  
    wmemset(des, ch, count); 
    wcout << L"After copying " << ch << L" -4 times" << endl; 
  
    for (int i = 0; i < count; i++) 
        putwchar(des[i]); 
  
    return 0; 
} 

Output:

Runtime Errors:
Segmentation Fault (SIGSEGV)

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