Output multiple columns and pre-increments in a single expression

Question

I am new to C, so plz sum1 help me. C code written

int i=3; printf("%d",++i + ++i); 

Complier gvs O / P = 9. How?
Thank you in advance

Answer 1

The results are undefined. You change a variable more than once in an expression (or a sequence point to be more precise).

Changing a variable more than once between points in a sequence is undefined, so don't do this.

Perhaps this is your compiler, as this particular case solves ++i + ++i as

• add the last ++i , getting 4, leaving me equal to 4
• add the first ++i , getting 5, leaving me equal to 5 (since the previous step I left as 4, increasing it to 5)
• sum two values, 4 + 5.

Another compiler, or if you change the optimization level, or slightly change the code, a different conclusion may arise.