/in/foo.cc: In function 'int f1(int, int)':
/in/foo.cc:5:6: warning: variable 'a' set but not used [-Wunused-but-set-variable]
  int a,b,z;
      ^
/in/foo.cc:5:8: warning: variable 'b' set but not used [-Wunused-but-set-variable]
  int a,b,z;
        ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:23:6: warning: unused variable 'x' [-Wunused-variable]
  int x,n,num=0,a0[10000]={0},a1[10000]={0},b0[10000]={0},b1[10000]={0};
      ^