View Compilation Error

355940_0_31552.cpp: In function `int main()':
355940_0_31552.cpp:24: error: `abs' undeclared (first use this function)
355940_0_31552.cpp:24: error: (Each undeclared identifier is reported only once for each function it appears in.)
355940_0_31552.cpp:46: error: `rerutn' undeclared (first use this function)
355940_0_31552.cpp:46: error: expected `;' before numeric constant