View Compilation Error

0_0_3911692_8205.cpp: In function `int main()':
0_0_3911692_8205.cpp:4: error: `scanf' undeclared (first use this function)
0_0_3911692_8205.cpp:4: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_3911692_8205.cpp:5: error: `getchar' undeclared (first use this function)
0_0_3911692_8205.cpp:21: error: `printf' undeclared (first use this function)