View Compilation Error

0_0_14756305_28736.c: In function 'main':
0_0_14756305_28736.c:16:15: error: 'sum' undeclared (first use in this function)
   printf("%d",sum);
               ^
0_0_14756305_28736.c:16:15: note: each undeclared identifier is reported only once for each function it appears in