View Compilation Error

0_0_28115062_23625.cpp: In function 'int main()':
0_0_28115062_23625.cpp:7:19: error: 'cin' was not declared in this scope
     while(getline(cin,str))
                   ^
0_0_28115062_23625.cpp:18:9: error: 'cout' was not declared in this scope
         cout<<num+1<<endl;
         ^
0_0_28115062_23625.cpp:18:22: error: 'endl' was not declared in this scope
         cout<<num+1<<endl;
                      ^