View Compilation Error

0_0_7136074_7603.cpp: In function `int main()':
0_0_7136074_7603.cpp:6: error: `scanf' undeclared (first use this function)
0_0_7136074_7603.cpp:6: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_7136074_7603.cpp:12: error: `gets' undeclared (first use this function)
0_0_7136074_7603.cpp:31: error: `printf' undeclared (first use this function)