What is Memory Leak? How can we avoid?

Memory leak occurs when programmers create a memory in heap and forget to delete it.
Memory leaks are particularly serious issues for programs like daemons and servers which by definition never terminate.

/* Function with memory leak */
#include <stdlib.h>

void f()
{

int *ptr = (int *) malloc(sizeof(int));

/* Do some work */

return; /* Return without freeing ptr*/

}

To avoid memory leaks, memory allocated on heap should always be freed when no longer needed.

/* Function without memory leak */

#include <stdlib.h>;

void f()
{
   int *ptr = (int *) malloc(sizeof(int));

/* Do some work */

   free(ptr);

return;
}