/in/foo.cc: In function 'int main()':
/in/foo.cc:7:67: warning: variable 'c2' set but not used [-Wunused-but-set-variable]
     int a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,a2,b2,c2,d2; 
                                                                   ^~
/in/foo.cc:7:70: warning: variable 'd2' set but not used [-Wunused-but-set-variable]
     int a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,a2,b2,c2,d2; 
                                                                      ^~