Thread: Help with explaining a C program

  1. #1
    Registered User
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    May 2018
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    Question Help with explaining a C program

    Hello.I am having trouble of understanding why this codes outputs these numbers: 9,1,9,3,8,5. Can someone please explain how the program works?
    Code:
    :
    
    #include <stdio.h>
    #include <stdlib.h>
    
    
    int main()
    {
    int arr[6]={9,7,9,8,8,9};
    int i=-1;
    while(i<5){
        i=i+2;
        arr[i]=i;
    }
    for(i=0;i<6;i++){
        printf("%d, ",arr[i]);
    }
    return 0;
    }

  2. #2
    Registered User
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    Why don't you take your best guess, and explain what you think happens, then let us help you with the parts you don't know.
    What can this strange device be?
    When I touch it, it gives forth a sound
    It's got wires that vibrate and give music
    What can this thing be that I found?

  3. #3
    Lurking whiteflags's Avatar
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    Through an additive process, a position in the array is chosen, and then assigned, such that the position number and the number stored are the same.

  4. #4
    and the hat of int overfl Salem's Avatar
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    Try adding debug print statements where you're confused.

    Say
    Code:
    while(i<5){
        i=i+2;
        arr[i]=i;
        printf("arr[%d]=%d\n", i, i );
    }
    When you get bored of editing code to find out what variables contain, learn how to use a debugger to really get control of how your program behaves.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

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