View Compilation Error

0_0_17805123_15328.cpp:4:2: error: 'string' does not name a type
  string s;  
  ^
0_0_17805123_15328.cpp: In function 'int main()':
0_0_17805123_15328.cpp:12:11: error: 'cin' was not declared in this scope
     while(cin>>n && n)  
           ^
0_0_17805123_15328.cpp:14:33: error: 'memset' was not declared in this scope
         memset(sum,0,sizeof(sum));  
                                 ^
0_0_17805123_15328.cpp:17:22: error: 'struct Balloon' has no member named 's'
            cin>>c[i].s;  
                      ^
0_0_17805123_15328.cpp:22:25: error: 'struct Balloon' has no member named 's'
                 if(c[i].s==c[j].s)  
                         ^
0_0_17805123_15328.cpp:22:33: error: 'struct Balloon' has no member named 's'
                 if(c[i].s==c[j].s)  
                                 ^
0_0_17805123_15328.cpp:35:9: error: 'cout' was not declared in this scope
         cout<<c[r].s<<endl;  
         ^
0_0_17805123_15328.cpp:35:20: error: 'struct Balloon' has no member named 's'
         cout<<c[r].s<<endl;  
                    ^
0_0_17805123_15328.cpp:35:23: error: 'endl' was not declared in this scope
         cout<<c[r].s<<endl;  
                       ^