View Compilation Error

0_0_22065406_25880.c: In function 'main':
0_0_22065406_25880.c:7:5: error: expected expression before '/' token
     //freopen("sample.txt", "r", stdin);
     ^
0_0_22065406_25880.c:10:5: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
     for(int T = 1; T <= cases; ++T)
     ^
0_0_22065406_25880.c:10:5: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_22065406_25880.c:15:9: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
         for(int i = 0; i < N; ++i)
         ^
0_0_22065406_25880.c:19:18: error: redefinition of 'i'
         for (int i = 0; i < N; ++i)
                  ^
0_0_22065406_25880.c:15:17: note: previous definition of 'i' was here
         for(int i = 0; i < N; ++i)
                 ^
0_0_22065406_25880.c:19:9: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
         for (int i = 0; i < N; ++i)
         ^