View Compilation Error

0_0_18733859_29018.c: In function 'main':
0_0_18733859_29018.c:17:3: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
   for(long w=1;w<=n;w++)
   ^
0_0_18733859_29018.c:17:3: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_18733859_29018.c:26:1: error: expected expression before '/' token
 //  printf("%f,%f\n",a,b);
 ^
0_0_18733859_29018.c:30:1: error: expected expression before '/' token
 //   printf("%f   ",y[k]);
 ^
0_0_18733859_29018.c:32:3: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
   for(long r=0;r<i;r++)
   ^
0_0_18733859_29018.c:34:4: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
    for(long t=0;t<i;t++)
    ^
0_0_18733859_29018.c:43:3: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
   for(long o=0;o<i;o++)
   ^