View Compilation Error

0_0_37749961_20048.cpp:7:5: error: conflicting declaration 'int t'
 int t , n;
     ^
0_0_37749961_20048.cpp:4:5: note: previous declaration as 'int t [20]'
 int t[20],len[20];
     ^
0_0_37749961_20048.cpp: In function 'int main()':
0_0_37749961_20048.cpp:12:10: error: lvalue required as decrement operand
  while(t --){
          ^