Question

In the following code, what is the first line that introduces a memory leak into the program?

(Type the line number into the box below)

1: #include <stdio.h>

2: #include <stdlib.h>

3: #include <string.h>

4: int main() {

5:            char *word1 = NULL;

6:            word1 = malloc(sizeof(char) * 11);

7:            word1 = "bramble";

8:            char *word2 = NULL:

9:            word2 = malloc(sizeof(char) * 11);

10:          word2 = word1;

11:          return 0;

12: }

Answer 1

Memory leak: A memory is allocated for a pointer variable in a program and some operations are performed on this pointer variable. If the program terminates without freeing(deallocation) the memory allocated to the pointer variable, then there will be memory leak in the program.

This type of situation is called as memory leak.

In the given program, the memory is allocated for the char pointer variable word1 and word2.

• After creating the memory for word1 in line 6, word1 is assigned with value “bramble”. Here, word1 is modifying without deallocating the memory space of word1.
• Similarly, after creating the memory for word2 in line 9, word2 is assigned with value word1. Here, word2 is modifying without deallocating the memory space of word2.

If the memory is not released or freed, then memory leakage will occur. The program without memory leakage is shown below:

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

int main()

{

                char *word1 = NULL;

                word1 = malloc(sizeof(char) * 11);

                free(word1); //sine here modifying word1,

                                  // first free the space given to word1

                word1 = "bramble";

                char *word2 = NULL;

                word2 = malloc(sizeof(char) * 11);

                free(word2); //since here modifying word2,

                                      // first free the space given to word2

                word2 = word1;

                return 0;

}

Therefore, the first line that introduces a memory leak into the program is line 7 and the next line is line 10.