View Compilation Error

0_0_31174077_30612.cpp: In function 'int main()':
0_0_31174077_30612.cpp:4:22: error: 'scanf' was not declared in this scope
  while(scanf("%d", &t) != EOF) {
                      ^
0_0_31174077_30612.cpp:4:27: error: 'EOF' was not declared in this scope
  while(scanf("%d", &t) != EOF) {
                           ^
0_0_31174077_30612.cpp:6:30: error: 'printf' was not declared in this scope
    printf("Score is error!\n");
                              ^
0_0_31174077_30612.cpp:10:16: error: 'printf' was not declared in this scope
    printf("A\n");
                ^
0_0_31174077_30612.cpp:14:16: error: 'printf' was not declared in this scope
    printf("B\n");
                ^
0_0_31174077_30612.cpp:18:16: error: 'printf' was not declared in this scope
    printf("C\n");
                ^
0_0_31174077_30612.cpp:22:16: error: 'printf' was not declared in this scope
    printf("D\n");
                ^
0_0_31174077_30612.cpp:26:16: error: 'printf' was not declared in this scope
    printf("E\n");
                ^