View Compilation Error

0_0_13711141_22251.cpp: In function 'int main()':
0_0_13711141_22251.cpp:18:11: error: 'cin' was not declared in this scope
     while(cin>>n>>k){  
           ^
0_0_13711141_22251.cpp:32:9: error: 'cout' was not declared in this scope
         cout<<s[n][k]<<endl;  
         ^
0_0_13711141_22251.cpp:32:24: error: 'endl' was not declared in this scope
         cout<<s[n][k]<<endl;  
                        ^