我在编写用于支付图书的代码方面遇到了问题。
它必须添加数量，如果ISBN号相同，但它不会增加数量，它会产生另一个具有相同ISBN的值......我无法弄清楚如何在现有值中添加数量。我认为问题出在searchinventory函数或addbook本身。
#include <stdio.h>
#define MAX_BOOKS 10
#define MAX_TITLE_SIZE 20
struct Book {
int _isbn; //International Standard Book Number
float _price; //Book Price
int _year; // Publication Year
char _title[MAX_TITLE_SIZE]; //Book Title
int _qty; //Book Quantity
};
//////////////////////////////////
void flushKeyboard(void);
void displayInventory(const struct Book book[],const int size);
void addBook(struct Book book[],int *size);
int searchInventory(const struct Book book[],const int isbn,const int size);
void checkPrice(const struct Book book[],const int size);
///////////////////////////////////
void flushKeyboard(void)
{
char enter;
do{
scanf("%c",&enter);
}while(enter != '\n');
}
void displayInventory(const struct Book book[],const int size){
int i = 0;
printf("\n\nInventory\n");
printf("===================================================\n");
printf("ISBN Title Year Price Quantity\n");
printf("---------+-------------------+----+-------+--------\n");
for(i=0;i<size;i++){
printf("%-10.0d%-20s%-5d$%-8.2f%-8d\n",book[i]._isbn,book[i]._title,book[i]._year,book[i]._price,book[i]._qty);
}
printf("===================================================\n\n");
}
//////////////////////////////////////////////
void addBook(struct Book book[],int *size){
int result = -1;
int _isbn;
int _qty;
if(*size == MAX_BOOKS){
printf("the inventory is full");
}
else{
printf("ISBN:");
scanf("%d",&_isbn);
result = searchInventory(&book[*size],_isbn,*size);
printf("_isbn = %d\n",_isbn);
printf("Quantity:");
scanf("%d",&_qty);
if(result != -1){
book[result]._isbn = _isbn;
book[result]._qty = book[result]._qty + _qty;
printf("The book exists in the repository, quantity is updated.\n");
printf("book[result]._qty is %d\n",book[result]._qty);
printf("book[*size]._qty is %d\n",book[*size]._qty);
}
if(result == -1){
book[*size]._isbn = _isbn;
book[*size]._qty = _qty;
printf("Title:");
scanf(" %20[^\n]",book[*size]._title);
flushKeyboard();
printf("Year:");
scanf("%d",&book[*size]._year);
printf("Price:");
scanf("%f",&book[*size]._price);
printf("The book is successfully added to the inventory.\n\n");
}
}
}
//////////////////////////////////////////////////////////////////////////////
int searchInventory(const struct Book book[],const int isbn,const int size){
int i = 0;
int result = -1;
for(i=0;i<size;i++){
if(isbn == (book[i]._isbn)){
result = i;
return result;
break;
}
}
return result;
}
/////////////////////////////////////////////////////////////////////////////
void checkPrice(const struct Book book[],const int size){
int isbn;
int i = 0;
printf("Please input the ISBN number of the book\n\n");
scanf("%d",&isbn);
i = searchInventory(&book[size],isbn,size);
printf("Book %d costs %.2d\n\n",isbn,book[size]._price);
}
int main(void){
struct Book book[MAX_BOOKS];
int size=0;
int option;
printf("Welcome to the Book Store\n=========================\n");
do{
printf("Please select from the following options:\n");
printf("1) Display the inventory.\n");
printf("2) Add a book to the inventory.\n");
printf("3) Check price.\n");
printf("0) Exit.\n");
printf("\nSelect: ");
scanf("%d",&option);
switch(option){
case 1:
if(size == 0){
printf("The inventory is empty!\n");
printf("===================================================\n\n");
}
else{
displayInventory(book,size);
}
break;
case 2:
//SIZE++;
addBook(book,&size);
size++;
break;
case 3:
printf("Please select input the ISBN number of the book: \n\n");
//checkPrice();
break;
case 0:
printf("Goodbye!\n");
break;
default: //wrong input
printf("Invalid input, try again:\n");
break;
}
}while(option!=0);
return 0;
}
答案 0 :(得分：0)
如果以下代码可以帮助您，请尝试。我试图修复错误，以便添加新书可以计算书店中该特定书籍的数量。
测试运行程序：
Welcome to the Book Store
=========================
Please select from the following options:
1) Display the inventory.
2) Add a book to the inventory.
3) Check price.
0) Exit.
Select: 1
The inventory is empty!
===================================================
Please select from the following options:
1) Display the inventory.
2) Add a book to the inventory.
3) Check price.
0) Exit.
Select: 2
ISBN:12345678
_isbn = 12345678
Quantity:2
Title:FOO
Year:1991
Price:19
The book is successfully added to the inventory.
Please select from the following options:
1) Display the inventory.
2) Add a book to the inventory.
3) Check price.
0) Exit.
Select: 1
Inventory
===================================================
ISBN Title Year Price Quantity
---------+-------------------+----+-------+--------
12345678 FOO 1991 $19.00 2
===================================================
Please select from the following options:
1) Display the inventory.
2) Add a book to the inventory.
3) Check price.
0) Exit.
Select: 2
ISBN:87654321
_isbn = 87654321
Quantity:1
Title:BAZ
Year:1987
Price:4
The book is successfully added to the inventory.
Please select from the following options:
1) Display the inventory.
2) Add a book to the inventory.
3) Check price.
0) Exit.
Select: 1
Inventory
===================================================
ISBN Title Year Price Quantity
---------+-------------------+----+-------+--------
12345678 FOO 1991 $19.00 2
87654321 BAZ 1987 $4.00 1
===================================================
Please select from the following options:
1) Display the inventory.
2) Add a book to the inventory.
3) Check price.
0) Exit.
Select: 2
ISBN:12345678
_isbn = 12345678
Quantity:3
The book exists in the repository, quantity is updated.
book[result]._qty is 5
Please select from the following options:
1) Display the inventory.
2) Add a book to the inventory.
3) Check price.
0) Exit.
Select: 1
Inventory
===================================================
ISBN Title Year Price Quantity
---------+-------------------+----+-------+--------
12345678 FOO 1991 $19.00 5
87654321 BAZ 1987 $4.00 1
===================================================
Please select from the following options:
1) Display the inventory.
2) Add a book to the inventory.
3) Check price.
0) Exit.
Select:
代码
#include <stdio.h>
#include <stdint.h>
#define MAX_BOOKS 10
#define MAX_TITLE_SIZE 20
struct Book {
int64_t _isbn; //International Standard Book Number
float _price; //Book Price
int _year; // Publication Year
char _title[MAX_TITLE_SIZE]; //Book Title
int _qty; //Book Quantity
};
//////////////////////////////////
//////////////////////////////////
void flushKeyboard(void);
void displayInventory(const struct Book book[],const int size);
int addBook(struct Book book[],int *size);
int searchInventory(const struct Book book[],const int isbn,const int size);
void checkPrice(const struct Book book[],const int size);
///////////////////////////////////
void flushKeyboard(void)
{
char enter;
do{
scanf("%c",&enter);
}while(enter != '\n');
}
void displayInventory(const struct Book book[],const int size){
int i = 0;
printf("\n\nInventory\n");
printf("===================================================\n");
printf("ISBN Title Year Price Quantity\n");
printf("---------+-------------------+----+-------+--------\n");
for(i=0;i<size;i++){
printf("%-10.0d%-20s%-5d$%-8.2f%-8d\n",book[i]._isbn,book[i]._title,book[i]._year,book[i]._price,book[i]._qty);
}
printf("===================================================\n\n");
}
//////////////////////////////////////////////
int addBook(struct Book book[],int *size){
int result = -1;
int _isbn;
int _qty;
if(*size == MAX_BOOKS){
printf("the inventory is full");
}
else{
printf("ISBN:");
scanf("%d",&_isbn);
result = searchInventory(book,_isbn,*size);
printf("_isbn = %d\n",_isbn);
printf("Quantity:");
scanf("%d",&_qty);
if(result != -1){
book[result]._isbn = _isbn;
book[result]._qty = book[result]._qty + _qty;
printf("The book exists in the repository, quantity is updated.\n");
printf("book[result]._qty is %d\n",book[result]._qty);
//printf("book[*size]._qty is %d\n",book[*size]._qty);
return 0;
}
else {
book[*size]._isbn = _isbn;
book[*size]._qty = _qty;
printf("Title:");
scanf(" %19[^\n]",book[*size]._title);
flushKeyboard();
printf("Year:");
scanf("%d",&book[*size]._year);
printf("Price:");
scanf("%f",&book[*size]._price);
printf("The book is successfully added to the inventory.\n\n");
return 1;
}
}
}
//////////////////////////////////////////////////////////////////////////////
int searchInventory(const struct Book book[],const int isbn,const int size){
int i = 0;
int result = -1;
for(i=0;i<size;i++){
if(isbn == (book[i]._isbn)){
result = i;
return result;
break;
}
}
return result;
}
/////////////////////////////////////////////////////////////////////////////
void checkPrice(const struct Book book[],const int size){
int isbn;
int i = 0;
printf("Please input the ISBN number of the book\n\n");
scanf("%d",&isbn);
i = searchInventory(&book[size],isbn,size);
printf("Book %d costs %.2f\n\n",isbn,book[i]._price);
}
int main(void){
struct Book book[MAX_BOOKS];
int size=0;
int option;
printf("Welcome to the Book Store\n=========================\n");
do{
printf("Please select from the following options:\n");
printf("1) Display the inventory.\n");
printf("2) Add a book to the inventory.\n");
printf("3) Check price.\n");
printf("0) Exit.\n");
printf("\nSelect: ");
scanf("%d",&option);
switch(option){
case 1:
if(size == 0){
printf("The inventory is empty!\n");
printf("===================================================\n\n");
}
else{
displayInventory(book,size);
}
break;
case 2:
//SIZE++;
size = size + addBook(book,&size);
//size++;
break;
case 3:
printf("Please select input the ISBN number of the book: \n\n");
//checkPrice();
break;
case 0:
printf("Goodbye!\n");
break;
default: //wrong input
printf("Invalid input, try again:\n");
break;
}
}while(option!=0);
return 0;
}