View Compilation Error

0_0_18061757_10419.cpp: In function 'int main()':
0_0_18061757_10419.cpp:20:11: error: 'cin' was not declared in this scope
     while(cin>>n>>k){  
           ^
0_0_18061757_10419.cpp:34:9: error: 'cout' was not declared in this scope
         cout<<s[n][k]<<endl;  
         ^
0_0_18061757_10419.cpp:34:24: error: 'endl' was not declared in this scope
         cout<<s[n][k]<<endl;  
                        ^