/in/foo.cc: In function 'int main()':
/in/foo.cc:15:15: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   if(a=1&&b!=N) {
               ^
/in/foo.cc:19:22: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   } else if(b=N&&a!=1) {
                      ^
/in/foo.cc:23:22: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   } else if(a=1&&b==N) {
                      ^
/in/foo.cc:22:8: warning: array subscript is below array bounds [-Warray-bounds]
    hf[a][b]=k;
    ~~~~^
/in/foo.cc:29:11: warning: array subscript is below array bounds [-Warray-bounds]
    hf[a][b]=k;
    ~~~~~~~^