View Compilation Error

0_0_1563331_10406.cpp: In function `void read_network()':
0_0_1563331_10406.cpp:31: error: `strcmp' undeclared (first use this function)
0_0_1563331_10406.cpp:31: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_1563331_10406.cpp:32: error: `strcpy' undeclared (first use this function)
0_0_1563331_10406.cpp: In function `void output()':
0_0_1563331_10406.cpp:144: error: `qsort' undeclared (first use this function)