/in/foo.c: In function 'circularLeftShift':
/in/foo.c:11:30: warning: implicit declaration of function 'pow' [-Wimplicit-function-declaration]
     return firstDigit * (int)pow(10, digitCount - 1) + num / 10;
                              ^~~
/in/foo.c:11:30: warning: incompatible implicit declaration of built-in function 'pow'
/in/foo.c:11:30: note: include '<math.h>' or provide a declaration of 'pow'