View Compilation Error

0_0_17355595_19070.c: In function 'f':
0_0_17355595_19070.c:21:13: error: too few arguments to function 'f'
   return (a*f(n-1)+b*f(n-2))%7;
             ^
0_0_17355595_19070.c:15:5: note: declared here
 int f(int a,int b,int n)
     ^
0_0_17355595_19070.c:21:22: error: too few arguments to function 'f'
   return (a*f(n-1)+b*f(n-2))%7;
                      ^
0_0_17355595_19070.c:15:5: note: declared here
 int f(int a,int b,int n)
     ^