在 C++ 中使用字符数组验证用户输入 [英] User Input Validation Using Character Array in C++

问题描述

我正在创建一个 C++ 程序来使用 C++ 中的函数来验证图书 ID.如果输入有效，程序必须返回 1，如果输入无效，程序必须返回 0.输入模式:123-AB-12345" 这将被视为有效输入.有效输入为: (a) 总字符数必须为 12 (b) 前三个字符必须为 1 到 9 之间的整数.(c) 第 4 和第 7 个字符必须是汉字-".(d) 最后 5 个字符必须是 1 到 9 的整数.

I am creating a c++ program to validate book ID using function in c++. The program must return 1 if the input is valid and 0 if the input is invalid. INPUT Pattern: "123-AB-12345" This will be considered as a valid input. The valid input is: (a) Total characters must be 12 (b) First three characters must be integers from 1 to 9 each. (c) 4th and 7th characters must be hiphen "-". (d) Last 5 characters must be integers from 1 to 9 each.

我尝试了以下方法，但没有得到想要的答案.需要帮助请

I tried the following way but I am not getting the desired answer. Need help plz

#include<iostream>
using namespace std;
bool isValidBookId(char bookId[13]);
int main()
{
    char book[13];
    cin.getline(book,12);
    bool id = isValidBookId(book);
    cout<<id;
}
bool isValidBookId(char bookId[13])
{
    int i;
    bool check1,check2,check3,check4,check5,check6;
    check1=check2=check3=check4=check5=true;
    if(bookId[12]=='\0'){
        check1=true;
    }       
    if(bookId[3]=='-')
    {
        check2=true;
    }
    if(bookId[6]=='-')
    {
        check3=true;
    }
    for(i=0; i<3;i++){
        if(bookId[i]>=0 || bookId[i]<=9)
        {
            check4=true;
        }
    }
    if(bookId[i]>= 'A' || bookId[i]<= 'Z')
    {
        check5=true;
    }
    for(i=7; i<12; i++)
    {
        if(bookId[i]>=0 || bookId[i]<=9)
        {
            check6=true;
        }
    }
    if(check1==true && check2==true && check3==true && check4==true && check5==true && check6==true)
    {
        return true;
    }
    else
    {
        return false;
    }
}

推荐答案

您的代码中存在一些错误.

There's a few errors that you have in your code.

首先，您将所有检查初始化为 true，并且永远不要将任何内容设置为 false，因此答案将始终为 true.实际上，您希望将它们全部初始化为 false，并在满足所有条件时更改为 true，或者假设 true，并设置为false 不满足条件时.

First, you initialize all your checks to true, and never set anything to false, so the answer will always be true. Realistically, you want to initialize them all to false, and change to true when all the conditions are met, or assume true, and set to false when the condition is not met.

其次，您对 0-9 值的检查不正确.您不能将 bookId[i] 与 0 进行比较，而是要将其与字符 '0' 进行比较.另请注意，您的问题还说 1-9 而不是 0-9

Second, your check for the values 0-9 is incorrect. You cannot compare bookId[i] to 0, you want to compare it to the character '0'. Also note that the question you have also says 1-9 not 0-9

第三，您对 A-Z 的检查不正确(注意，此问题也适用于 0-9).你的代码基本上是 bookId[i] 大于或等于 'A' 或小于或等于 Z，这是 总是 将是 true.

Third, your check for A-Z is incorrect (note, this issue also applies to 0-9). You're code basically says is bookId[i] greater than or equal to 'A' OR less than or equal to Z, which is always going to be true.

我已经在下面编写了您的代码:

I've written your code below:

bool isValidBookId( char bookId[13] ) {

    if ( bookId[12] != '\0' )
        return false;
    if ( bookId[3] != '-' )
        return false;
    if ( bookId[6] != '-' )
        return false;

    for ( int i = 0; i < 3; i++ ) {
        if ( bookId[i] < '1' || bookId[i] > '9' ) {
            return false;
        }
    }
    for ( int i = 4; i < 6; i++ ) {
        if ( bookId[i] < 'A' || bookId[i] > 'Z' ) {
            return false;
        }
    }
    for ( int i = 7; i < 12; i++ ) {
        if ( bookId[i] < '1' || bookId[i] > '9' ) {
            return false;
        }
    }

    return true;
}

此方法不需要任何布尔变量.相反，我假设 true(最后一个 return 语句)并尝试证明 false.一旦出现false，您无需进行任何其他检查即可返回.

This method doesn't require any Boolean variables. Instead, I assume true (the last return statement) and instead try to prove false. As soon as something is false, you can return without doing any other checks.

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