View Compilation Error

0_0_5128935_32290.cpp: In function `int main(int, char**)':
0_0_5128935_32290.cpp:10: error: `strlen' undeclared (first use this function)
0_0_5128935_32290.cpp:10: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_5128935_32290.cpp:11: error: `strcmp' undeclared (first use this function)
0_0_5128935_32290.cpp:46: error: `system' undeclared (first use this function)