View Compilation Error

0_0_21357821_27687.cpp: In function 'int main()':
0_0_21357821_27687.cpp:10:20: error: 'xx' was not declared in this scope
         scanf("%s",xx);
                    ^
0_0_21357821_27687.cpp:11:20: error: 'yy' was not declared in this scope
         scanf("%s",yy);
                    ^