Please someone explain me this code in C language

Question

this code is solution of this problem https://codeforces.com/problemset/problem/136/A in codeforces .... i understand the problem and i solved it but i don't understand this solution.. please someone explain me this code

int n,a[101],i,j;

main()
{
    n||scanf("%d",&n);
    i-n&&(scanf("%d",a),a[*a]=++i,main(),printf("%d ",a[++j]));
}

Welcome to Stack Overflow! Please try to ask specific questions. What specific parts of this code do you not understand? What have you tried to understand so far? — GraphicsMuncher, Sep 13 '20 at 20:05
Please see [“Explain X to me” questions: How to react?](https://meta.stackoverflow.com/questions/271468/explain-x-to-me-questions-how-to-react) for why you need to narrow what you do not understand. I do not think the title you've chosen makes this Question easy to find from a search. — Scratte, Sep 14 '20 at 07:27
Don't bother with understanding this solution. It is obfuscation and horribly slow recursion on top of that. Looks like "code golf" and not a real program. — Lundin, Sep 14 '20 at 09:39
Also, `main()` instead of `int main()` with a function that lacks `return 0;` is invalid in any form of C. In C90, it would invoke undefined behavior if the caller (OS) used the result, in C99 and beyond it won't compile. — Lundin, Sep 14 '20 at 09:42

Andreas Wenzel · Accepted Answer · 2020-09-13T20:23:25.660

Due to short-circuit evaluation of the operators || and &&, the code you posted is equivalent to the following:

int n,a[101],i,j;

main()
{
    if ( n == 0 )
    {
        scanf( "%d", &n );
    }

    if ( i - n != 0 )
    {
        scanf( "%d", a );

        i++;
        a[*a] = i;

        main(); //recursive function call

        j++;
        printf( "%d ", a[j] );
    }
}

In order to understand how this code works, all you have to do is run it line by line in a debugger, while monitoring the values of all variables.

Please someone explain me this code in C language

1 Answers1