/in/foo.cc:3:71: error: two or more data types in declaration of 'build'
 void build(int xnode,int ynode,int xbegin,int xend,int ybegin,int yend){
                                                                       ^
/in/foo.cc: In function 'void update(int, int, int, int, int, int)':
/in/foo.cc:30:13: error: 'xleft' was not declared in this scope
  if(xbegin>=xleft&&xend<=xright&&ybegin>=yleft&&yend<=yright)return tree[xnode][ynode];
             ^~~~~
/in/foo.cc:30:26: error: 'xright' was not declared in this scope
  if(xbegin>=xleft&&xend<=xright&&ybegin>=yleft&&yend<=yright)return tree[xnode][ynode];
                          ^~~~~~
/in/foo.cc:30:42: error: 'yleft' was not declared in this scope
  if(xbegin>=xleft&&xend<=xright&&ybegin>=yleft&&yend<=yright)return tree[xnode][ynode];
                                          ^~~~~
/in/foo.cc:30:55: error: 'yright' was not declared in this scope
  if(xbegin>=xleft&&xend<=xright&&ybegin>=yleft&&yend<=yright)return tree[xnode][ynode];
                                                       ^~~~~~
/in/foo.cc:30:69: error: 'tree' was not declared in this scope
  if(xbegin>=xleft&&xend<=xright&&ybegin>=yleft&&yend<=yright)return tree[xnode][ynode];
                                                                     ^~~~
/in/foo.cc:30:86: error: return-statement with a value, in function returning 'void' [-fpermissive]
  if(xbegin>=xleft&&xend<=xright&&ybegin>=yleft&&yend<=yright)return tree[xnode][ynode];
                                                                                      ^
/in/foo.cc:33:42: error: 'down' was not declared in this scope
  down(xnode,ynode,xbegin,xend,ybegin,yend);
                                          ^
/in/foo.cc:31:6: warning: unused variable 'xmid' [-Wunused-variable]
  int xmid=(xbegin+xend)/2;
      ^~~~
/in/foo.cc:32:6: warning: unused variable 'ymid' [-Wunused-variable]
  int ymid=(ybegin+yend)/2;
      ^~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:37:16: error: 'N' was not declared in this scope
  scanf("%d%d",&N,&M);
                ^
/in/foo.cc:37:19: error: 'M' was not declared in this scope
  scanf("%d%d",&N,&M);
                   ^