View Compilation Error

0_0_29799480_24954.cpp: In function 'int main()':
0_0_29799480_24954.cpp:7:5: error: 'cin' was not declared in this scope
     cin>>t;
     ^
0_0_29799480_24954.cpp:28:9: error: 'cout' was not declared in this scope
         cout<<sum<<endl;
         ^
0_0_29799480_24954.cpp:28:20: error: 'endl' was not declared in this scope
         cout<<sum<<endl;
                    ^