View Compilation Error

0_0_29459262_9437.cpp: In function 'int main()':
0_0_29459262_9437.cpp:4:21: error: 'scanf' was not declared in this scope
 while(~scanf("%d",&a))
                     ^
0_0_29459262_9437.cpp:6:39: error: 'printf' was not declared in this scope
  if (a>100) printf("Score is error!\n"); 
                                       ^
0_0_29459262_9437.cpp:7:29: error: 'printf' was not declared in this scope
  else if(a>=90) printf("A\n");
                             ^
0_0_29459262_9437.cpp:8:29: error: 'printf' was not declared in this scope
  else if(a>=80) printf("B\n");
                             ^
0_0_29459262_9437.cpp:9:29: error: 'printf' was not declared in this scope
  else if(a>=70) printf("C\n");
                             ^
0_0_29459262_9437.cpp:10:29: error: 'printf' was not declared in this scope
  else if(a>=60) printf("D\n");
                             ^
0_0_29459262_9437.cpp:11:28: error: 'printf' was not declared in this scope
  else if(a>=0) printf("E\n"); 
                            ^