View Compilation Error

0_0_2953678_18284.cpp: In function `int gcd(int, int)':
0_0_2953678_18284.cpp:13: error: `abs' undeclared (first use this function)
0_0_2953678_18284.cpp:13: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_2953678_18284.cpp:13: error: `Min' undeclared (first use this function)