View Compilation Error

0_0_18823303_9451.cpp: In function 'int main()':
0_0_18823303_9451.cpp:3:21: error: 'scanf' was not declared in this scope
  while(scanf("%d",&t)!=EOF){
                     ^
0_0_18823303_9451.cpp:3:24: error: 'EOF' was not declared in this scope
  while(scanf("%d",&t)!=EOF){
                        ^
0_0_18823303_9451.cpp:5:30: error: 'printf' was not declared in this scope
    printf("Score is error!\n");
                              ^
0_0_18823303_9451.cpp:10:23: error: 'printf' was not declared in this scope
   case  9:printf("A\n");break;
                       ^