C library function - memset()

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Description

The C library function void *memset(void *str, int c, size_t n) copies the character c (an unsigned char) to the first n characters of the string pointed to, by the argument str.

Declaration

Following is the declaration for memset() function.

void *memset(void *str, int c, size_t n)

Parameters

• str − This is a pointer to the block of memory to fill.

• c − This is the value to be set. The value is passed as an int, but the function fills the block of memory using the unsigned char conversion of this value.

• n − This is the number of bytes to be set to the value.

Return Value

This function returns a pointer to the memory area str.

Example

The following example shows the usage of memset() function.

#include <stdio.h>
#include <string.h>

int main () {
   char str[50];

   strcpy(str,"This is string.h library function");
   puts(str);

   memset(str,'$',7);
   puts(str);
   
   return(0);
}

Let us compile and run the above program that will produce the following result −

This is string.h library function
$$$$$$$ string.h library function