C's pow function refuses to work with variable exponent

Question

Let\'s say I have the following code snippet:

int i; double value;
for(i = 0; i < CONSTANT; i++) {
  value = (double)pow(2, i);
}

Trying

Answer 1

The code for pow is part of the math library. You need to link in that library (in addition to the C library that is linked in by default).

To do that, with gcc, specify -lm on the compiler invocation

gcc ... -lm