View Compilation Error

0_0_32780112_20292.cpp: In function 'int main()':
0_0_32780112_20292.cpp:4:21: error: 'scanf' was not declared in this scope
  scanf("%d %d",&a,&b);
                     ^
0_0_32780112_20292.cpp:6:19: error: 'printf' was not declared in this scope
  printf("%d\n",a+b);
                   ^