View Compilation Error

0_0_32104405_27203.cpp: In function 'int main()':
0_0_32104405_27203.cpp:27:5: error: 'add' was not declared in this scope
     add = 0;
     ^
0_0_32104405_27203.cpp:29:8: error: 'add' was not declared in this scope
    y1+=add;
        ^