View Compilation Error

534747_0_0_10233.cpp: In function `int main()':
534747_0_0_10233.cpp:13: error: `scanf' undeclared (first use this function)
534747_0_0_10233.cpp:13: error: (Each undeclared identifier is reported only once for each function it appears in.)
534747_0_0_10233.cpp:13: error: `EOF' undeclared (first use this function)
534747_0_0_10233.cpp:20: error: `sort' undeclared (first use this function)
534747_0_0_10233.cpp:21: error: `hash' undeclared (first use this function)
534747_0_0_10233.cpp:21: error: `memset' undeclared (first use this function)
534747_0_0_10233.cpp:39: error: `printf' undeclared (first use this function)