View Compilation Error

879258_0_0_23166.cpp: In function `int main()':
879258_0_0_23166.cpp:19: error: `cin' undeclared (first use this function)
879258_0_0_23166.cpp:19: error: (Each undeclared identifier is reported only once for each function it appears in.)
879258_0_0_23166.cpp:55: error: `qsort' undeclared (first use this function)
879258_0_0_23166.cpp:84: error: `cout' undeclared (first use this function)
879258_0_0_23166.cpp:84: error: `endl' undeclared (first use this function)