C language Supermarket Management System design

This article shares the specific code of C language supermarket management system design for your reference. The specific content is as follows

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define NUM 5

struct item{
 char brand[20];
 char id[10];
 float in_price;
 float out_price;
 int storage;
};
struct item_node{
 struct item wanted;
 int amount;
 struct item_node *next;
};

int menu();
void establish();
void dis_all();
void shop_cart();
int cart_menu();
void add();
void display();
void calculate();

struct item goods[NUM];
struct item_node *cart;


void main()
{
 printf("***********************************\n");
 printf("   Welcome to the supermarket management system \n");
 printf("***********************************\n");
 while(1)
 {
 switch(menu())
 {
 case 1:
 establish();break;
 case 2:
 dis_all();break;
 case 3:
 shop_cart();break;
 case 4:
 calculate();break;
 case 5:
 printf(" Thanks for using it. Bye !\n");
 exit(0);
 }
 }
}

int menu()
{
 char str[5];
 int select;
 printf("\n\n Please select the number to operate \n");
 printf("1. Establish inventory information \n");
 printf("2. Display all information \n");
 printf("3. The shopping cart \n");
 printf("4. settlement \n");
 printf("5. exit \n");
 printf(" Please select the corresponding number 1--5");
 while(1)
 {
 fflush(stdin);
 gets(str);
 select=atoi(str);
 if(select<1||select>5)
 printf(" Input error, please retype :");
 else
 break;
 
 }
 return select;
 
}

void dis_all()
{
 int i;
 FILE *fp;
 fp=fopen("goods","r");
 for(i=0;(fread(goods+i,sizeof(struct item),1,fp))!=0;i++)
 {
 printf("---------------------------------\n");
 printf(" goods   Of the goods   The unit price    inventory \n");
 printf("%s%7s%7.2f%8d\n",goods[i].id,goods[i].brand,goods[i].out_price,goods[i].storage);
 
 }
 fclose(fp);
}


void shop_cart()
{
 while(1)
 {
 switch(cart_menu())
 {
 case 1:
 display();break;
 case 2:
 add();break;
 case 3:
 return;
 }
 }
}
int cart_menu()
{
 char str[5];
 int select;
 printf("\n Please select Operation \n");
 printf("-----------------------\n");
 printf("1. Displays the current shopping list \n");
 printf("2. Add the goods \n");
 printf("3. exit \n");
 printf("-----------------------\n\n");
 while(1)
 {
 fflush(stdin);
 gets(str);
 select=atoi(str);
 if(select<1||select>3)
 printf(" Input error, please retype :");
 else
 break;
 }
 return select;
}

void display()
{
 struct item_node *p=cart;
 if(p==NULL){
 printf(" Empty shopping cart \n");
 return ;
 }
 while(p!=NULL){
 printf("----------------------------------\n");
 printf(" The article number      Of the goods   The unit price   The number of \n");
 printf("%10s%20s%7.2f%8d\n",p->wanted.id,p->wanted.brand,p->wanted.out_price,p->amount);
 p=p->next;
 }
}

void add()
{
 FILE *fp;
 int i,n;
 char str[20];
 char choice1,choice2;
 struct item_node *p,*p1;
 do
 {
 printf(" Enter the name or article number of the item you want : ");
 fflush(stdin);
 gets(str);
 if((fp=fopen("goods","r"))==NULL){
 printf(" Failed to open file \n");
 continue;
 }
 for(i=0;fread(goods+i,sizeof(struct item),1,fp)!=0;i++){
 if((strcmp(goods[i].brand,str)==0||strcmp(goods[i].id,str)==0)&&goods[i].storage!=0){
 printf(" The necessary items have been found : \n");
 printf("---------------------\n");
 printf(" The article number   Of the goods   The unit price   inventory \n");
 printf("%s%6s%3.2f%4d\n",goods[i].id,goods[i].brand,goods[i].out_price,goods[i].storage);
 printf(" Please enter the required quantity : ");
 scanf("%d",&n);
 if(n>goods[i].storage){
  printf(" Insufficient inventory \n");
  break;
 }
 printf("\n Whether or not to buy ?(Y/N)");
 fflush(stdin);
 choice1=getchar();
 if(choice1=='Y'||choice1=='y'){
  p1=(struct item_node*)malloc(sizeof(struct item_node));
  if(p1==NULL){
  printf(" Memory request failed !\n");
  exit(1);
  }
  p1->amount=n;
  p1->wanted=goods[i];
  p1->next=NULL;
  p=cart;
  if(cart==NULL)
  cart=p1;
  else{
  while(p->next!=NULL)
  p=p->next;
  p1->next=p->next;
  p->next=p1;
  }
 }
 break;
 }
 }
 if(i==NUM)
 printf(" No required items were found \n");
 fclose(fp);
 printf(" Whether to continue shopping ?(Y/N)");
 fflush(stdin);
 choice2=getchar();
 }while(choice2=='Y'||choice2=='y');
}


void establish(){
 FILE *fp;
 int i;
 printf(" Please enter the cargo information in turn :\n");
 printf("----------------------------\n");
 for(i=0;i<NUM;i++)
 {
 printf(" Of the goods : ");
 fflush(stdin);
 gets(goods[i].brand);
 printf(" The article number : ");
 fflush(stdin);
 gets(goods[i].id);
 printf(" Purchase price : ");
 fflush(stdin);
 scanf("%f",&goods[i].in_price);
 printf(" Whistle price : ");
 fflush(stdin);
 scanf("%f",&goods[i].out_price);
 printf(" The number of : ");
 fflush(stdin);
 scanf("%d",&goods[i].storage);
 printf("\n");
 }
 if((fp=fopen("goods","w"))==NULL){
 printf(" File creation failed .\n");
 return;
 }
 fwrite(goods,sizeof(struct item),NUM,fp);
 fclose(fp);
}

void calculate()
{
 float total=0,pay;
 struct item_node *p;
 int i;
 FILE *fp;
 printf(" Here is the shopping list : \n");
 display();
 if((fp=fopen("goods","r"))==NULL){
 printf(" Failed to open file : \n");
 return;
 }
 for(i=0;(fread(goods+i,sizeof(struct item),1,fp))!=0;i++);
 fclose(fp);
 p=cart;
 while(p!=NULL){
 total+=p->wanted.out_price*p->amount;
 for(i=0;strcmp(goods[i].id,p->wanted.id)!=0;i++);
 goods[i].storage-=p->amount;
 p=p->next;
 }
 printf(" A total of  %7.2f",total);
 printf("\n Enter the actual amount paid : ");
 scanf("%f",&pay);
 printf(" Real pay :   %7.2f  The change :   %7.2f",pay,pay-total);
 if((fp=fopen("goods","w"))==NULL){
 printf(" Failed to open file .\n");
 return;
 }
 fwrite(goods,sizeof(struct item),NUM,fp);
 fclose(fp);
}