View Compilation Error

0_0_36568765_8213.cpp: In function 'int main()':
0_0_36568765_8213.cpp:87:33: error: 'struct Q' has no member named 'popl'
         } else printf("%d\n", R.popl());
                                 ^
0_0_36568765_8213.cpp:89:23: error: 'struct Q' has no member named 'popr'
             int x = L.popr();
                       ^
0_0_36568765_8213.cpp:94:23: error: 'struct Q' has no member named 'popl'
             int x = R.popl();
                       ^