The order of execution of parameters is undefined in C programming. Here it may execute from left to right or from right to left. The order depends on the implementation.

#include <stdio.h>

void function(int a, int b) 
{
    printf("%d %d\\n", a, b);
}

int main(void)
{
    int a = 1;
    function(a++, ++a);
    return 0;
}