View Compilation Error

0_0_26317450_22830.cpp: In function 'int main()':
0_0_26317450_22830.cpp:4:30: error: 'scanf' was not declared in this scope
     while(scanf("%d %d",&a,&b) != EOF)
                              ^
0_0_26317450_22830.cpp:4:35: error: 'EOF' was not declared in this scope
     while(scanf("%d %d",&a,&b) != EOF)
                                   ^
0_0_26317450_22830.cpp:6:27: error: 'printf' was not declared in this scope
         printf("%d\n", a+b);
                           ^