View Compilation Error

0_0_18246618_27993.cpp: In function 'void printint(int)':
0_0_18246618_27993.cpp:42:14: error: 'o' was not declared in this scope
  while (d) { o[++top] = d % 10 + '0'; d /= 10; }
              ^
0_0_18246618_27993.cpp:43:21: error: 'o' was not declared in this scope
  while (top)putchar(o[top--]);
                     ^