View Compilation Error

0_0_23520412_29045.cpp: In function 'int main()':
0_0_23520412_29045.cpp:13:22: error: 'a' was not declared in this scope
                 if ((a[j - 1] == 'x' && a[j * i - 1] == 'r' && a[j * i * i - 1] == 'y'))||(a[j-1]=='y'&&a[j*i-1]=='r'&&a[j*i*i-1]=='x')){
                      ^
0_0_23520412_29045.cpp:13:89: error: expected primary-expression before '||' token
                 if ((a[j - 1] == 'x' && a[j * i - 1] == 'r' && a[j * i * i - 1] == 'y'))||(a[j-1]=='y'&&a[j*i-1]=='r'&&a[j*i*i-1]=='x')){
                                                                                         ^