YehiaMedhat Posts - Answer Overflow

YehiaMedhat

CPSComputer Programming - Seneca Polytechnic College

•Created by YehiaMedhat on 9/17/2023 in #ask-a-question

Why iterating through an array by incrementing pointer gives such output?

This is my code snippet, I was trying to print the elements of the arr by accessing its values from the pointers.

#include <stdio.h>

/**
 * main - entry point
 * Return: Always sucess (0)
 */

int main(void)
{
    /* Declaring vars */
    int arr[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    int i;
    int* parr = arr;

    /* Try to iterate by pointer incrementation */
    for (; *parr != '\0'; parr++)
    {
        /* output: arr elements plus an unknown element */
        printf("%d ", *parr);     
    }

    printf("\n");

    /* Try to iterate by index */
    for (i = 0; i < 10; i++)
    {
        /* output: arr elements exactly as they are */
        printf("%d ", arr[i]); 
    }
    
    printf("\n");

    /* Try to iterate by both index and pointer */
    for (i = 0; i < 10; i++)
    {
        /* output: arr elements in hexadecimal format */
        printf("%p ", *&arr[i]); 
    }

    return (0);
}

#include <stdio.h>

/**
 * main - entry point
 * Return: Always sucess (0)
 */

int main(void)
{
    /* Declaring vars */
    int arr[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    int i;
    int* parr = arr;

    /* Try to iterate by pointer incrementation */
    for (; *parr != '\0'; parr++)
    {
        /* output: arr elements plus an unknown element */
        printf("%d ", *parr);     
    }

    printf("\n");

    /* Try to iterate by index */
    for (i = 0; i < 10; i++)
    {
        /* output: arr elements exactly as they are */
        printf("%d ", arr[i]); 
    }
    
    printf("\n");

    /* Try to iterate by both index and pointer */
    for (i = 0; i < 10; i++)
    {
        /* output: arr elements in hexadecimal format */
        printf("%p ", *&arr[i]); 
    }

    return (0);
}

This is the output; look at the first line of the output, why this 33 showed up?

1 2 3 4 5 6 7 8 9 10 **33**
1 2 3 4 5 6 7 8 9 10
0000000000000001 0000000000000002 0000000000000003 0000000000000004 0000000000000005 0000000000000006 0000000000000007 0000000000000008 0000000000000009 000000000000000A

1 2 3 4 5 6 7 8 9 10 **33**
1 2 3 4 5 6 7 8 9 10
0000000000000001 0000000000000002 0000000000000003 0000000000000004 0000000000000005 0000000000000006 0000000000000007 0000000000000008 0000000000000009 000000000000000A

Thanks in advance 😇

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