How this output came?

Question

#include<stdio.h>
int main() {
int a = 10;
printf("%d %d %d",a,++a,a++);
return 0;
}

the output is 12 12 10
But how?
Please Explain.

Answer 1

My bad. After reading this stackoverflow question, the function parameters aren't evaluated in a defined order.
https://stackoverflow.com/questions/376278/parameter-evaluation-order-before-a-function-calling-in-c

Meaning this code might give different results on different compilers.

Answer 2

It evaluates the arguments randomly. In this case, it executes a++ first which returns 10, then ++a which returns 12 and a which also returns 12.

Answer 3

in all the printf statements in c does it do calculation from right to left?