View Compilation Error

0_0_36324976_32389.cpp: In function 'int main()':
0_0_36324976_32389.cpp:32:8: error: 'b' was not declared in this scope
     x+=b;
        ^
0_0_36324976_32389.cpp:33:8: error: 'a' was not declared in this scope
     y-=a;
        ^