Question

for c language

What function is used to deallocate dynamic memory when it is no longer required by your program? In your answer give the name of the function and its syntax, and how the C runtime system knows how much memory to deallocate. Give an appropriate example showing typical usage of this function

Answer 1

free function is used to deallocate dynamic memory when it is no longer required.

Syntax of free function

free(pointer name)

example void(*ptr)

pointername is the name of the pointer which pointsto a memory block previously allocated with malloc, calloc or realloc to be deallocated.

Example of usage of free function

#include <stdio.h>
#include <string.h>
int main () {
char *str;
/* Initial memory allocation */
str = (char *) malloc(15);
strcpy(str, "hello");
  

/* Reallocating memory */
str = (char *) realloc(str, 25);
strcat(str, "world");

/* Deallocate allocated memory */
free(str);

return(0);
}