120i is incorrect syntax. Use either one of these below: 1) remove the i's 2) multiply by i

Adapted Code

1. // option 1
   
2. for (int i = 0; i <100; i++) {
3.   for (int j = 120; j < 120+10; j++) {
4.   }
5. }
6. 
   
7. // option 2
   
8. for (int i = 0; i <100; i++) {
9.   for (int j = 120*i; j < 120*i+10; j++) {
10.   }
11. }