View Compilation Error

0_0_7875124_6479.cpp: In function `int main()':
0_0_7875124_6479.cpp:16: error: `cin' undeclared (first use this function)
0_0_7875124_6479.cpp:16: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_7875124_6479.cpp:26: error: `qsort' undeclared (first use this function)
0_0_7875124_6479.cpp:43: error: `cout' undeclared (first use this function)
0_0_7875124_6479.cpp:43: error: `endl' undeclared (first use this function)