View Compilation Error

0_0_9420531_17114.cpp: In function `int main()':
0_0_9420531_17114.cpp:6: error: `scanf' undeclared (first use this function)
0_0_9420531_17114.cpp:6: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_9420531_17114.cpp:7: error: `getchar' undeclared (first use this function)
0_0_9420531_17114.cpp:11: error: `gets' undeclared (first use this function)
0_0_9420531_17114.cpp:23: error: `printf' undeclared (first use this function)