View Compilation Error

0_0_5953991_12296.cpp: In function `int main()':
0_0_5953991_12296.cpp:4: error: `scanf' undeclared (first use this function)
0_0_5953991_12296.cpp:4: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_5953991_12296.cpp:4: error: `EOF' undeclared (first use this function)
0_0_5953991_12296.cpp:6: error: `a' undeclared (first use this function)
0_0_5953991_12296.cpp:21: error: `printf' undeclared (first use this function)