View Compilation Error

0_0_37363130_7866.cpp: In function 'int main()':
0_0_37363130_7866.cpp:5:14: error: 'gets' was not declared in this scope
  while(gets(a)!=NULL){
              ^
0_0_37363130_7866.cpp:16:20: error: 'printf' was not declared in this scope
   printf("%d\n",sum);
                    ^