Unexpected output when executing left-shift by 32 bits

Question

When I do a left shift of a hex I get -1 as output with the following code:

unsigned int i,j=0;
i= (0xffffffff  << (32-j));
printf(\"%d\",i);
         


        

Answer 1

It's undefined behavior to left-shit 32 or greater on a 32-bit integer. That's what the error is about.

C11 6.5.7 Bitwise shift operators

The integer promotions are performed on each of the operands. The type of the result is that of the promoted left operand. If the value of the right operand is negative or is greater than or equal to the width of the promoted left operand, the behavior is undefined.