/in/foo.cc: In function 'int main()':
/in/foo.cc:41:10: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
   if(M[i]<j&M[i]!=x){
      ~~~~^~
/in/foo.cc:7:6: warning: unused variable 'k' [-Wunused-variable]
  int k[n];
      ^
/in/foo.cc:4:12: warning: 'f' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int n,m,c,f,x,j;
            ^