View Compilation Error

0_0_32813602_7390.cpp: In function 'int main()':
0_0_32813602_7390.cpp:7:5: error: 'cin' was not declared in this scope
     cin>>nCases;
     ^
0_0_32813602_7390.cpp:18:53: error: 'gong_yue_shu' was not declared in this scope
             int quan1_yue = gong_yue_shu(quan1, day1);
                                                     ^
0_0_32813602_7390.cpp:26:56: error: 'gong_bei_shu' was not declared in this scope
             int quan_result = gong_bei_shu(quan1, quan2);
                                                        ^
0_0_32813602_7390.cpp:35:17: error: 'cout' was not declared in this scope
                 cout<<quan_result<<'/'<<day_result<<endl;
                 ^
0_0_32813602_7390.cpp:35:53: error: 'endl' was not declared in this scope
                 cout<<quan_result<<'/'<<day_result<<endl;
                                                     ^
0_0_32813602_7390.cpp:37:17: error: 'cout' was not declared in this scope
                 cout<<quan_result<<endl;
                 ^
0_0_32813602_7390.cpp:37:36: error: 'endl' was not declared in this scope
                 cout<<quan_result<<endl;
                                    ^