Problem with realloc

[wd_kendrick]

Here is a snippet of code that displays the problem I am having with realloc in a much larger program:

#include <stdlib.h>
#include <stdio.h>

int main()
{
    
    int *int_array,counter, size,size1;
    
    printf("How many members in the array do you want: ");
    scanf("%d",&size);

// Allocates memory for the int_array

    int_array=(int *)malloc(size*sizeof(int));

// Places a value in each index position    

    for(counter=0;counter<size;counter++)
        int_array[counter]=10+counter;

    printf("\nThe array has the following elements: \n");

// Prints values

    for(counter=0;counter<size;counter++)    
        printf("%d\n",int_array[counter]);
    


    printf("What would you like the new size to be: ");
    scanf("%d",&size1);
    
// Should reallocate the array to size size1

    int_array=realloc(int_array,size);

    printf("\nThe array now has the following elements: \n");

// Runs until counter is equal to the original size...When I increase the size using
// realloc the values up until the original size should remain unchanged, but 
// they are not when i print them out

    for(counter=0;counter<size;counter++)    
        printf("%d\n",int_array[counter]);
    system("PAUSE");
    return 0;
}

HERE IS THE OUTPUT I GET: (I ran this on two machines and it came up with the same numbers)

Like I said, I am running into this problem in a much larger project, if anyone can help it would be greatly appreciated.

How many members in the array do you want: 10

The array has the following elements:
10
11
12
13
14
15
16
17
18
19
What would you like the new size to be: 11
10
11
12
13
196697
15
3998784
3998784
18
393302

[leiming]

int_array=realloc(int_array,size1);

You forget to multiplus sizeof(int) to size.

LeiMing.

[birkelbach]

You also are not actually using the new size1. You might also want to test the return value from realloc before you reassign your existing pointer.

new_array = realloc(int_array, size1 * sizeof(int));
if(new_arr) int_array = new_array;
else return -1; /* or whatever else */

[wd_kendrick]

Wow...I fell like a dummy.

int_array=realloc(int_array,size1*sizeof(int));

works perfectly.

...Also, thanks for the error checking hints...always a good idea

[Elysia]

Also note that it is a bad idea to cast the return of malloc in a C program (explanation is in FAQ).