/in/foo.cc: In function 'void merge()':
/in/foo.cc:24:11: warning: unused variable 'k' [-Wunused-variable]
   int i,j,k;  
           ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:37:11: warning: unused variable 'k' [-Wunused-variable]
   int i,j,k;  
           ^