sequence-points – IT Nursery

Why are these constructs using pre and post-increment undefined behavior?

April 18, 2022 by IT Nursery

#include <stdio.h> int main(void) { int i = 0; i = i++ + ++i; printf(“%d\n”, i); // 3 i = 1; i = (i++); printf(“%d\n”, i); // 2 Should be 1, no ? volatile int u = 0; u = u++ + ++u; printf(“%d\n”, u); // 1 u = 1; u = (u++); printf(“%d\n”, u); … Read more

Undefined behavior and sequence points

April 15, 2022 by IT Nursery

What are “sequence points”? What is the relation between undefined behaviour and sequence points? I often use funny and convoluted expressions like a[++i] = i;, to make myself feel better. Why should I stop using them? If you’ve read this, be sure to visit the follow-up question Undefined behavior and sequence points reloaded. (Note: This … Read more