View Compilation Error

0_0_20682063_8566.c: In function 'main':
0_0_20682063_8566.c:3:26: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
 { int t;scanf("%d" ,&t); for(int T=1 ;T <=t;T++) { int n;scanf("%d",&n); printf("Case #%d: %d\n",T,2*n-1) ; } }
                          ^
0_0_20682063_8566.c:3:26: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code