Question

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Could anyone explain these undefined behaviors (i = i++ + ++i , i = i++, etc…)

#include<stdio.h>
void call(int,int,int);

int main(){

int a=10;
call(a,a++,++a);
return 0;   
}

void call(int x,int y,int z){
printf("x=%d y=%d z=%d\n",x,y,z);
}

This code is giving me output of 12 11 12 when run it. Could someone explain exactly how this is happening?

Answer 1

The behaviour of your code is undefined since you’re changing a twice between sequence points:

call(a,a++,++a);