Array[i] = i++;

Question

int main()
{
    int arr[5]= {55}, i=0;
    while (i<5)
    {
        arr[i]= i++;
    }

    for(i=0; i<5; i++)
        printf("%d, ", arr[i]);

    return 0;
}

why is the output ( 55,0,1,2,3) Not ( 0,1,2,3,4)

Ps: I'm using GCC compiler

An easy way to figure this ambiguity out is to just never write code like this :) — Alexander, Jan 24 '22 at 01:51
@Alexander seconded:) Only teachers/TA/profs write such code:( — Martin James, Jan 24 '22 at 01:52

score 1 · Answer 1 · answered Jan 24 '22 at 01:48

1

This is undefined behavior.

Clang actually warns about it

warning: unsequenced modification and access to 'i' [-Wunsequenced]
arr[i]= i++;
   ~    ^

answered Jan 24 '22 at 01:48

Daniel A. White

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Array[i] = i++;

1 Answers1