View Compilation Error

0_0_30349093_12040.cpp:2:1: error: 'string' does not name a type
 string s;
 ^
0_0_30349093_12040.cpp: In function 'int main()':
0_0_30349093_12040.cpp:6:18: error: 'scanf' was not declared in this scope
     scanf("%d",&T);
                  ^
0_0_30349093_12040.cpp:9:9: error: 'cin' was not declared in this scope
         cin>>s;
         ^
0_0_30349093_12040.cpp:9:14: error: 's' was not declared in this scope
         cin>>s;
              ^
0_0_30349093_12040.cpp:20:9: error: 'cout' was not declared in this scope
         cout<<s<<endl;
         ^
0_0_30349093_12040.cpp:20:18: error: 'endl' was not declared in this scope
         cout<<s<<endl;
                  ^