View Compilation Error

0_0_33950814_26766.cpp:27:9: error: 'pair' does not name a type
 typedef pair<int,int> PII;
         ^
0_0_33950814_26766.cpp: In function 'int main(int, char**)':
0_0_33950814_26766.cpp:41:2: error: 'string' was not declared in this scope
  string x,y;
  ^
0_0_33950814_26766.cpp:42:8: error: 'cin' was not declared in this scope
  while(cin>>x>>y) {
        ^
0_0_33950814_26766.cpp:42:13: error: 'x' was not declared in this scope
  while(cin>>x>>y) {
             ^
0_0_33950814_26766.cpp:42:16: error: 'y' was not declared in this scope
  while(cin>>x>>y) {
                ^
0_0_33950814_26766.cpp:44:14: error: unable to deduce 'auto&&' from 'x'
   for(auto i:x ) {
              ^
0_0_33950814_26766.cpp:48:14: error: unable to deduce 'auto&&' from 'y'
   for(auto i:y) {
              ^
0_0_33950814_26766.cpp:52:23: error: 'printf' was not declared in this scope
   printf("%d\n", a + b);
                       ^