已知树的前序、中序，求后序的c++实现&已知树的后序、中序，求前序的c++实现

#include"iostream"
using namespace std;

int pre[30];
int in[30];
int post[30];

int indexOfRootIn(int start,int stop,int root){
    for(int j=start;j<=stop;j++){
        if(in[j]==root){
            return j;
        }
    }
    return -1;
}

void postOrder(int pre_start,int pre_end,int in_start,int in_end,int length){
    if(length==0)
        return;

    if(length==1){
        cout<<in[in_start]<<endl;
        return;
    }

    int root = pre[pre_start];
    int index = indexOfRootIn(in_start,in_end,root);

    int len1=(index-in_start);
    int len2=(in_end-index);

    postOrder(pre_start+1,pre_start+index,in_start,index-1,len1);
    postOrder(pre_start+index+1,pre_end,index+1,in_end,len2);

    cout<<root<<" "<<endl;
}

void preOrder(int post_start,int post_end,int in_start,int in_end,int length){
    if(length==0)
        return;

    if(length==1){
        cout<<in[in_start]<<endl;
        return;
    }

    int root = post[post_end];
    int index = indexOfRootIn(in_start,in_end,root);

    int len1= index-in_start;
    int len2= in_end-index;

    cout<<root<<" "<<endl;
    preOrder(post_start,post_start+index-1,in_start,index-1,len1);
    preOrder(post_start+index,post_end-1,index+1,in_end,len2);
}

int main(){
    int N;

    cin>>N;
    for(int i=0;i<N;i++){
        cin>>post[i];
    }
    for(int i=0;i<N;i++){
        cin>>in[i];
    }
    preOrder(0,N-1,0,N-1,N);
    return 0;
}