/in/foo.cc: In function 'int main()':
/in/foo.cc:42:8: warning: unused variable 'j' [-Wunused-variable]
  int i,j,k,x,y,z;
        ^
/in/foo.cc:42:10: warning: unused variable 'k' [-Wunused-variable]
  int i,j,k,x,y,z;
          ^
/in/foo.cc: In function 'void prim()':
/in/foo.cc:33:7: warning: 'j' may be used uninitialized in this function [-Wmaybe-uninitialized]
   b[k]=j;
   ~~~~^~