View Compilation Error

0_0_16541623_28004.cpp: In function 'int main()':
0_0_16541623_28004.cpp:20:2: error: 'cin' was not declared in this scope
  cin >> t;
  ^
0_0_16541623_28004.cpp:28:5: error: 'cout' was not declared in this scope
     cout << a[i-1] +n<< endl;
     ^
0_0_16541623_28004.cpp:28:25: error: 'endl' was not declared in this scope
     cout << a[i-1] +n<< endl;
                         ^