View Compilation Error

0_0_30104262_24613.cpp: In function 'int main()':
0_0_30104262_24613.cpp:27:30: error: 'a' was not declared in this scope
                 scanf(" %c",&a[i][j]);
                              ^
0_0_30104262_24613.cpp:33:32: error: 'z' was not declared in this scope
         printf("Case %d: %d\n",z,o);
                                ^