#include <stdio.h>

struct node{
    int e;
    struct node *next;
    };

struct dlie{
    struct node *first;
    struct node *tail;
    };

int build(struct dlie *D){
    D->first = D->tail = (struct node *)malloc(sizeof(struct node));
    if(!D->first)return 0;
    D->tail->next = NULL;
    return 1;
    }

int add(struct dlie *D,int e){
    D->tail->e = e;
    D->tail->next = (struct node *)malloc(sizeof(struct node));
    if(!D->tail->next)return 0;
    D->tail = D->tail->next;
    D->tail->next = NULL;
    return 1;
    }

int out(struct dlie *D){
    int e;
    if(D->first == D->tail){
        e = D->first->e;
        return e;
        }
    else{
        struct node *p;
        p = D->first;
        e = p->e;
        D->first = D->first->next;
        free(p);
        return e;
        }
    }

int done(int a,int b){
    if(a >= b)return 0;
    else return 1;
    }
void main(){
    struct dlie dlie1;
    int i = 0,a,b,c,e;
    scanf("%d",&c);
    build(&dlie1);
    for(i = 0;i < c;i++){
        scanf("%d",&a);
        scanf("%d",&b);
        add(&dlie1,done(a,b));
        }

    for(i = 0;i < c;i++){
        e = out(&dlie1);
        if(e == 0)
            printf("MMM BRAINS\n");
        else
            printf("NO BRAINS\n");
        }
    getch();
    }

北京大学程序在线评测系统poj里的问题2027，我的解决方案如上，但是提交之后却是编译错误，可我用WIN-TC可以运行我的题目，并且结果也是正确的。我就不知道为什么了，各位帮忙看一下！

Compile Error

Main.c
Main.obj : error LNK2019: unresolved external symbol _getch referenced in function _main
F:\temp\11568981.93225\Main.exe : fatal error LNK1120: 1 unresolved externals

这个是错误的提示。我不懂啊。谁会的帮帮忙，谢谢了。