电脑销售系统，修改一下，不会呀~

Question

#include<stdio.h> 
#include<stdlib.h>
#include<string.h>
#include<windows.h> 
struct Computer
{
       char  Name[50];
       char  Brand[50];
       char  Model[50];
       int   Sell_quantity;
       float Purchase_price;
       int   Stock_quantity;
       float Sell_price;
}Computer;


typedef  struct ComputerLink{
       char  Name[50];
       char  Brand[50];
       char  Model[50];
       int   Sell_quantity;
       float Purchase_price;
       int   Stock_quantity;
       float Sell_price;
}ComputerLink;

void MainMenu();
void InputComputer();
void DeleteComputer();
void AlterComputer();
void FindStockComputer();
void FindSellgoodComputer();
void FindTypeStockComputer();
void ComputerSell();
ComputerLink *CreatComputerLink();
void SaveComputer(ComputerLink *head);


int main(void){
MainMenu();
return 0; 
}

void MainMenu(){
int num;
printf("\n--------------------欢迎进入笔记本电脑销售系统----------------------------------");
printf("\n   --------------------------------------------------------------------------"); 
printf("\n服务编号；");
printf("\n1.添加笔记本电脑信息"); 
printf("\n2.删除笔记本电脑信息");
printf("\n3.修改笔记本电脑信息");
printf("\n4.查询笔记本库存现状");
printf("\n5.查询目前销售最高的笔记本");
printf("\n6.查询某品牌笔记本库存");
printf("\n7.笔记本销售"); 
printf("\n8.退出系统");
printf("\n9.格式化系统"); 
printf("\n Input；"); 
scanf("%d",&num);
switch(num){  
case 1:  InputComputer();
case 2:  DeleteComputer();
case 3:  AlterComputer();
case 4:  FindStockComputer();
case 5:  FindSellgoodComputer();
case 6:  FindTypeStockComputer();
case 7:  ComputerSell(); 
                    break; 
    }
 }
 
void InputComputer(){
  ComputerLink *p,*q,*head;
char Name[50];
  int x;
  printf("请按如下格式输入来添加笔记本信息：");
  printf("产品名称\t产品品牌\t产品型号\t销售数量\t进价\t库存数量\t售价\t");
  printf("当输入产品名称为0时则为停止录入！");
  printf("Input：");
  head=(ComputerLink *)malloc(sizeof(ComputerLink));
  p=head;
  scanf("%s",Name);
while(1){
  if(Name==0)  break;
else{
  q=(ComputerLink *)malloc(sizeof(ComputerLink));
  strcpy(q->Name,Name);
  scanf("%s%s%s%d%d%d%d",q->Name,q->Brand,q->Model,q->Sell_quantity,q->Purchase_price,q->Stock_quantity,q->Sell_price);
  p->next=q;
  p=q;
}
  scanf("%s",Name); 
}
  q->next=NULL;
  printf("保存成功！请按回车键继续！"); 
} 
void DeleteComputer(){
     ComputerLink *p,*head,*q;
     char  Name[50];
     int x;
     head=CreatComputerLink();
     scanf("%d",Name);
     q=head;
     p=q->next;
     while(p!=NULL&&(p->Name,Name)!=0){
         q=p;
         p=p->next;
         if(p==NULL){
         printf("改电脑不存在"); 
         }else{
        q->next=p->next;
        free(p);
        SaveComputer(head);
        printf("该电脑信息已被删除！\n"); 
         }
     }
}
void AlterComputer(){
    ComputerLink  *head,*p;
    char Name[50];
    int x;
    head=CreatComputerLink();
    scanf("%s",Name);
    p=head->next;
    for(p!=NULL&&strcmp(p->Name,Name)!=0;p=p->next)
    if(p==NULL){
         printf("没有找到该电脑信息！\n"); 
         }else{
    printf("请按如下格式输入来修改一条笔记本信息：");
    printf("产品名称\t产品品牌\t产品型号\t销售数量(修改后)\t进价(修改后)\t库存数量(修改后)\t售价(修改后)\t");
    scanf("%s%s%s%d%d%d%d",q->Name,q->Brand,q->Model,q->Sell_quantity,q->Purchase_price,q->Stock_quantity,q->Sell_price);
    SaveRaed(head); 
       }
   }
void FindStockComputer(){
    Computer C;
    char Name[50];
    FILE *fp;
    printf("Input:");
    scanf("%s",Name);
    if((fp=fopen("reader2.txt","r"))==NULL) {
    exit(0);
    }
    while(!feof(fp)){
    fscanf(fp,"%s%s%s%d%d%d%d",C.Name,C.Brand,C.Model,C.Sell_quantity,C.Purchase_price,C.Stock_quantity,C.sell_price); 
    if(strcmp(C.Name,Name)==0){
    printf("\n%s\t%s\t%s\t%d\t%d\t%d\t%d",C.Name,C.Brand,C.Model,C.Sell_quantity,C.Purchase_price,C.Stock_quantity,C.sell_price);
    break;
    }
  }
fclose(fp);
}
void FindSellgoodComputer(){
    Computer C;
    char Name[50];
    FILE *fp;
    printf("Input:");
    scanf("%s",Name);
    if((fp=fopen("reader2.txt","r"))==NULL) {
    exit(0);
    }
    while(!feof(fp)){
    fscanf(fp,"%s%s%s%d%d%d%d",C.Name,C.Brand,C.Model,C.Sell_quantity,C.Purchase_price,C.Stock_quantity,C.sell_price); 
    if(strcmp(C.Name,Name)==0){
    printf("\n%s\t%s\t%s\t%d\t%d\t%d\t%d",C.Name,C.Brand,C.Model,C.Sell_quantity,C.Purchase_price,C.Stock_quantity,C.sell_price);
    break;
    }
  }
fclose(fp);
}
void FindTypeStockComputer();
{
Computer C;
    char Name[50];
    FILE *fp;
    printf("Input:");
    scanf("%s",Name);
    if((fp=fopen("reader2.txt","r"))==NULL) {
    exit(0);
    }
    while(!feof(fp)){
    fscanf(fp,"%s%s%s%d%d%d%d",C.Name,C.Brand,C.Model,C.Sell_quantity,C.Purchase_price,C.Stock_quantity,C.sell_price); 
    if(strcmp(C.Name,Name)==0){
    printf("\n%s\t%s\t%s\t%d\t%d\t%d\t%d",C.Name,C.Brand,C.Model,C.Sell_quantity,C.Purchase_price,C.Stock_quantity,C.sell_price);
    break;
    }
  }
fclose(fp);
}

Answer 1

代码修改如下：

#include<stdio.h> 
#include<stdlib.h>
#include<string.h>


struct Computer
{
    char  Name[50];
    char  Brand[50];
    char  Model[50];
    int   Sell_quantity;
    float Purchase_price;
    int   Stock_quantity;
    float Sell_price;
};


typedef  struct _computerLink{
    struct Computer data;
    struct _computerLink* next;
}ComputerLink;

//因为下面的函数中都没有参数，所以这里定义全局变量来记录链表头
ComputerLink *head=0; // 链表头
char* filename="text.txt"; //文件名


void MainMenu();
void ReadFile(const char* file); //读取文件
void InputComputer();
void DeleteComputer();
void AlterComputer();
void FindStockComputer();
void FindSellgoodComputer();
void FindTypeStockComputer();
void ComputerSell();
ComputerLink *CreatComputerLink();
void SaveComputer(ComputerLink *head);


int main(void)
{
    MainMenu();
    return 0; 
}

void MainMenu()
{
    int num;
    
    ReadFile(filename);
    
    if(head==0)
    {
        printf("您是第一次使用该系统，请先录入笔记本销售信息！\n");
        printf("服务编号:\n");
        printf("1.新建笔记本电脑信息\n");
        printf("2.退出系统\n");
        scanf("%d",&num);
        switch(num)
        {
        case 1: InputComputer();break;
        case 2: return;
        }
    }

    while(1)
    {
        system("cls");
        printf("\n--------------------欢迎进入笔记本电脑销售系统----------------------------------");
        printf("\n   --------------------------------------------------------------------------"); 
        printf("\n服务编号；");
        printf("\n1.添加笔记本电脑信息"); 
        printf("\n2.删除笔记本电脑信息");
        printf("\n3.修改笔记本电脑信息");
        printf("\n4.查询笔记本库存现状");
        printf("\n5.查询目前销售最高的笔记本");
        printf("\n6.查询某品牌笔记本库存");
        printf("\n7.笔记本销售"); 
        printf("\n8.退出系统");
        printf("\n9.格式化系统"); 
        printf("\n Input:"); 
        scanf("%d",&num);
        switch(num)
        {  
        case 1:  InputComputer(); break;
        case 2:  DeleteComputer(); break;
        case 3:  AlterComputer(); break;
        case 4:  FindStockComputer();break;
        case 5:  FindSellgoodComputer();break;
        case 6:  FindTypeStockComputer();break;
        case 7:  ComputerSell(); break; 
        case 8: return ;
        case 9:break;
        }
    }

}
//从文件中读取数据，并返回链表头 。这个可能用不到，参考
void ReadFile(const char* file)
{
    ComputerLink *p,*t;
    FILE* fp = 0;
    

    fp = fopen(file,"r");
    if (fp == 0)
    {
        printf("file open error\n");
        return ;
    }
    //
    head = (ComputerLink*)malloc(sizeof(ComputerLink));
    head->next = 0;
    p = head;


    while(!feof(fp))
    {
        t = (ComputerLink*)malloc(sizeof(ComputerLink));
        t->next = 0;
        if( fscanf(fp,"%s %s %s %d %f %d %f",t->data.Name,t->data.Brand,t->data.Model,&t->data.Sell_quantity,&t->data.Purchase_price,&t->data.Stock_quantity,&t->data.Sell_price))
        {
            p->next = t;
            p = t;
        }else
        {
            free(t);
        }

    }
    
}

//写文件
void SaveComputer(ComputerLink *head)
{
    FILE *fp = 0;
    ComputerLink* p ;
    if (head==0 || head->next == 0) return;

    p = head->next;
    fp = fopen(filename,"w");
    while(p)
    {
        fprintf(fp,"%s %s %s %d %f %d %f",p->data.Name,p->data.Brand,p->data.Model,p->data.Sell_quantity,p->data.Purchase_price,p->data.Stock_quantity,p->data.Sell_price);
        p = p->next;
    }
    fclose(fp);
}

//新增电脑，要返回链表头
void InputComputer()
{
    ComputerLink *p,*q;
    char Name[50];

    system("cls");

    printf("请按如下格式输入来添加笔记本信息：");
    printf("产品名称\t产品品牌\t产品型号\t销售数量\t进价\t库存数量\t售价\t");
    printf("当输入产品名称为0时则为停止录入！");
    printf("Input：");
    if (head == 0)
    {
        head=(ComputerLink *)malloc(sizeof(ComputerLink));
        head->next = 0;
        p=head;
    }else
    {
        //将指针移动到链表末尾
        p = head;
        while(p->next)
            p = p->next;
    }


    while(1)
    {
        scanf("%s",Name);
        if(strcmp(Name,"0")==0)  break;
        else{
            q=(ComputerLink *)malloc(sizeof(ComputerLink));
            q->next = 0; //把下一个节点置0
            strcpy(q->data.Name,Name);
            //注意，因为前面已经读取了Name，所以这里就不需要再读取Name了，否则读取的数据不正确
            scanf("%s%s%d%f%d%f",q->data.Brand,q->data.Model,&q->data.Sell_quantity,&q->data.Purchase_price,&q->data.Stock_quantity,&q->data.Sell_price);
            p->next=q;
            p=q;
        }
    }

    printf("保存成功！请按回车键继续！"); 
    system("pause");
} 
//删除信息
void DeleteComputer()
{
    ComputerLink *p,*q;
    char  Name[50];
    //int x;
    //head=CreatComputerLink();
    system("cls");
    printf("请输入名称：");
    scanf("%d",Name);
    q=head;
    p=q->next;
    while(p!=NULL&&strcmp(p->data.Name,Name)!=0)
    {
        q=p;
        p=p->next;
    }
    if(p==NULL){
        printf("改电脑不存在"); 
    }else{
        q->next=p->next;
        free(p);
        SaveComputer(head);
        printf("该电脑信息已被删除！\n"); 
    }
    system("pause");
}
//更改电脑信息
void AlterComputer()
{
    ComputerLink *p;
    char Name[50];
    //int x;
    //head=CreatComputerLink();
    system("cls");
    printf("请输入名称：");
    scanf("%s",Name);
    p=head->next;
    for(;p!=NULL&&strcmp(p->data.Name,Name)!=0;p=p->next);
    if(p==NULL)
    {
        printf("没有找到该电脑信息！\n"); 
    }else{
        printf("请按如下格式输入来修改一条笔记本信息：");
        printf("产品名称\t产品品牌\t产品型号\t销售数量(修改后)\t进价(修改后)\t库存数量(修改后)\t售价(修改后)\t");
        scanf("%s%s%s%d%f%d%f",p->data.Name,p->data.Brand,p->data.Model,&p->data.Sell_quantity,&p->data.Purchase_price,&p->data.Stock_quantity,&p->data.Sell_price);
        SaveComputer(head); 
    }
    system("pause");
}
//查看库存
void FindStockComputer()
{
    ComputerLink* p;
    char Name[50];
    system("cls");
    printf("Input:");
    scanf("%s",Name);
    if(head==0) return;
    p = head->next;
    while(p && strcmp(p->data.Name,Name)!= 0)
        p = p->next;
    if(p==0)
        printf("未找到该电脑信息\n");
    else
        printf("%s\t%s\t%s\t%d\t%f\t%d\t%f\n",p->data.Name,p->data.Brand,p->data.Model,p->data.Sell_quantity,p->data.Purchase_price,p->data.Stock_quantity,p->data.Sell_price);

    system("pause");
}
//查看销售数量最多的
void FindSellgoodComputer()
{
    ComputerLink* p,*pmax=0;
    system("cls");
    if(head==0) return;
    p = head->next;
    pmax = head->next;

    p = p->next;
    while(p)
    {
        if(p->data.Sell_quantity > pmax->data.Sell_quantity)
            pmax = p;
        p = p->next;
    }
    printf("%s\t%s\t%s\t%d\t%f\t%d\t%f\n",pmax->data.Name,pmax->data.Brand,pmax->data.Model,pmax->data.Sell_quantity,pmax->data.Purchase_price,pmax->data.Stock_quantity,pmax->data.Sell_price);
    system("pause");
}
//查看某品牌库存
void FindTypeStockComputer()
{
    ComputerLink* p;
    char Name[50];
    system("cls");
    if(head==0) return;
    printf("Input:");
    scanf("%s",Name);

    p = head->next;
    while(p && strcmp(p->data.Brand,Name)!=0) //品牌应该是Brand字段，不是Name字段
        p = p->next;
    if(p==0)
        printf("未找到该品牌\n");
    else
        printf("%s\t%s\t%s\t%d\t%f\t%d\t%f\n",p->data.Name,p->data.Brand,p->data.Model,p->data.Sell_quantity,p->data.Purchase_price,p->data.Stock_quantity,p->data.Sell_price);

    system("pause");    
}
//电脑销售（这个函数要实现什么功能？）
void ComputerSell()
{
    //
}