c 中用于用户定义函数的未解析外部符号

问题描述

我对编程非常陌生，在我的课程中，我们学习了 c 语言，因此请怜悯我编写的糟糕代码，并且编译器由于错误而无法运行该程序，因此我很难确定哪里出了问题。回到主要问题我得到未解析的外部符号...在 function_main 中引用，我真的不知道我在哪里搞砸了

#include<stdio.h>
char displayMenu(void);
void ViewBooks();
void SearchBookPrice();
void UpdateBookPrice();


int main()
{
    char userchoice;
    int bookID[5] = { 200,230,500,540,700 };
    char bookTitle[5][50] = { {"Using @R_379_4045@ion Technology 12th Edition" },{ "Beyond HTML" },{"Build Your Own PC"},{"Instant Java Servlets"},{"DIgital Image: A Practical Guide"} };
    float bookPrice[5] = { 100.30,50.40,47,83.30,22.90 };

    do
    {
        userchoice = displayMenu();
        if (userchoice == 'V')
            ViewBooks();
        else if (userchoice == 'S')
            SearchBookPrice();
        else if (userchoice == 'U')
            UpdateBookPrice();
    } while (userchoice != 'E');

    printf("Thank you for using our system. Have a nice day!\n");

    return 0;
}

char displayMenu(void)
{
    char choice;

    printf("*************************************************************************\n");
    printf("V:View Books  S:Search Book Price  U:Update Book Price  E:Exit");
    printf("*************************************************************************\n");
 
    do
    {
        printf("Enter your choice: ");
        scanf(" %c",&choice);

        if (choice != 'V' && choice != 'S' && choice != 'U' && choice != 'E')
            printf("Invalid Choice\n");

    } while (choice != 'V' && choice != 'S' && choice != 'U' && choice != 'E');
    

    return choice;
}

void ViewBooks(int bookID[],float bookPrice[])
{
    printf("%d   Using @R_379_4045@ion Technology 12th Edition   $%f\n",bookID[0],bookPrice[0]);
    printf("%d   Beyond HTML   $%f\n",bookID[1],bookPrice[1]);
    printf("%d   Build Your Own PC   $%f\n",bookID[2],bookPrice[2]);
    printf("%d   Instant Java Servlets  $%f\n",bookID[3],bookPrice[3]);
    printf("%d   Digital Image: A Pratical Guide  $%f\n",bookID[4],bookPrice[4]);

    return;
}

void SearchBookPrice(int bookID[5],char bookTitle[5][50],float bookPrice[5])
{
    int idsearch,i= 0,match = -1;
    printf("*************************************************************************\n");
    printf("Search by book ID\n");
    printf("*************************************************************************\n");

    printf("Enter book ID: ");
    scanf("%d",&idsearch);

    while (i<5 && match==-1)
    {
        if (bookID[i] == idsearch)
            match = i;
        i++;
    }



    if (match == -1)
        printf("Please refer to the customer service for assitance");
    else
    {
        printf("The book id is : %d\n",&idsearch);
        printf("The price of %s is %f",bookTitle[match],bookPrice[match]);
    }

    return;

}

void UpdateBookPrice(int bookID[5],i = 0,match = -1;
    printf("Enter book ID: ");
    scanf("%d",&idsearch);
    while (i < 5 && match == -1)
    {
        if (bookID[i] == idsearch)
            match = i;
        i++;
    }
    if (match == -1)
        printf("The book ID is not found. Please make sure the book ID is correct");
    else
    {
        printf("Current book price is %f\n",bookPrice[match]);
        printf("Enter new price for (%d-%s): ",bookID[match],bookTitle[match]);
        scanf("%f",&bookPrice[match]);
    }
    return;
}

解决方法

您的函数声明与函数体不匹配。

这是工作代码。

#include<stdio.h>
char DisplayMenu(void);
void ViewBooks(int bookID[],float bookPrice[]);
void SearchBookPrice(int bookID[5],char bookTitle[5][50],float bookPrice[5]);
void UpdateBookPrice(int bookID[5],float bookPrice[5]);


int main()
{
    char userchoice;
    int bookID[5] = { 200,230,500,540,700 };
    char bookTitle[5][50] = { {"Using Information Technology 12th Edition" },{ "Beyond HTML" },{"Build Your Own PC"},{"Instant Java Servlets"},{"DIgital Image: A Practical Guide"} };
    float bookPrice[5] = { 100.30,50.40,47,83.30,22.90 };

    do
    {
        userchoice = DisplayMenu();
        if (userchoice == 'V')
            ViewBooks(bookID,bookPrice);
        else if (userchoice == 'S')
            SearchBookPrice(bookID,bookTitle,bookPrice);
        else if (userchoice == 'U')
            UpdateBookPrice(bookID,bookPrice);
    } while (userchoice != 'E');

    printf("Thank you for using our system. Have a nice day!\n");

    return 0;
}

char DisplayMenu(void)
{
    char choice;

    printf("*************************************************************************\n");
    printf("V:View Books  S:Search Book Price  U:Update Book Price  E:Exit");
    printf("*************************************************************************\n");
 
    do
    {
        printf("Enter your choice: ");
        scanf(" %c",&choice);

        if (choice != 'V' && choice != 'S' && choice != 'U' && choice != 'E')
            printf("Invalid Choice\n");

    } while (choice != 'V' && choice != 'S' && choice != 'U' && choice != 'E');
    

    return choice;
}

void ViewBooks(int bookID[],float bookPrice[])
{
    printf("%d   Using Information Technology 12th Edition   $%f\n",bookID[0],bookPrice[0]);
    printf("%d   Beyond HTML   $%f\n",bookID[1],bookPrice[1]);
    printf("%d   Build Your Own PC   $%f\n",bookID[2],bookPrice[2]);
    printf("%d   Instant Java Servlets  $%f\n",bookID[3],bookPrice[3]);
    printf("%d   Digital Image: A Pratical Guide  $%f\n",bookID[4],bookPrice[4]);

    return;
}

void SearchBookPrice(int bookID[5],float bookPrice[5])
{
    int idsearch,i= 0,match = -1;
    printf("*************************************************************************\n");
    printf("Search by book ID\n");
    printf("*************************************************************************\n");

    printf("Enter book ID: ");
    scanf("%d",&idsearch);

    while (i<5 && match==-1)
    {
        if (bookID[i] == idsearch)
            match = i;
        i++;
    }



    if (match == -1)
        printf("Please refer to the customer service for assitance");
    else
    {
        printf("The book id is : %d\n",&idsearch);
        printf("The price of %s is %f",bookTitle[match],bookPrice[match]);
    }

    return;

}

void UpdateBookPrice(int bookID[5],i = 0,match = -1;
    printf("Enter book ID: ");
    scanf("%d",&idsearch);
    while (i < 5 && match == -1)
    {
        if (bookID[i] == idsearch)
            match = i;
        i++;
    }
    if (match == -1)
        printf("The book ID is not found. Please make sure the book ID is correct");
    else
    {
        printf("Current book price is %f\n",bookPrice[match]);
        printf("Enter new price for (%d-%s): ",bookID[match],bookTitle[match]);
        scanf("%f",&bookPrice[match]);
    }
    return;
}