C++中的错误检查

Question

出于某种原因我不能让它工作 =/ 一整天都在谷歌搜索，但没有运气

我创建了一个名为 cFunc 的函数来进行错误检查，每次用户输入后我都会调用它，让他们知道他们添加的信息无效。但由于某种原因，这是行不通的。任何帮助都会很棒！

#include "math.h"
#include <iostream>
#include <limits>

using namespace std;

int loanAmount; //amount of the loan
double loanInterest; // the loan interest rate
int loanYears; //years of the loan
int loanTerm = loanYears; //loan term in months
double loanPay; //variable for outputting the payment

int main()
{
cout<<"Enter Loan Amount";
cin>>loanAmount;
cFunc();
cout<<"Enter Loan Interest";
cin>>loanInterest;
cFunc();
cout<<"Enter Loan Years";
cin>>loanYears;
cFunc();


loanPay = (loanAmount * loanInterest) / (1 - pow(1+loanInterest,-loanYears)); //Formula to figure mortgage payment amount

cout<< "Your Monthly Payment Amount is: $"<< loanPay; //prints out monthly payment amount
return 0;
}

void cFunc(){
    int main(){
    cout << "Enter an int: ";
    int x = 0;
    while(!(cin >> x)){
        cin.clear();
        cin.ignore(numeric_limits<streamsize>::max(), '\n');
        cout << "Invalid input.  Try again: ";
    }
    cout << "You enterd: " << x << endl;           
    }
    return x;
}

Answer 1

来自 pastebin 上的代码

void _loanAmount(int x) {
    cout<<"Enter Loan Amount";
    cin>>loanAmount;

    while (!(cin >> x)) {
        cin.clear();
        cin.ignore(numeric_limits<streamsize>::max(),'\n');
        cout << "Please enter a numerical value" << endl;
    }
}

应该是

void _loanAmount() {
    cout<<"Enter Loan Amount";
    while (!(cin >> loanAmount)) {
        cin.clear();
        cin.ignore(numeric_limits<streamsize>::max(),'\n');
        cout << "Please enter a numerical value" << endl;
    }
}

您可能在没有充分理解自己在做什么的情况下改编在其他地方看到的代码。正如之前的评论之一所说，这是货物崇拜编程。停止谷歌搜索并阅读一本书是我的建议。

Answer 2

首先我看到：在函数中你声明了一个 main. 第二：我包含了函数的原型第三：该函数已被声明为 void，并且 return 是一个 int，为什么？

这是有效的代码。至少，逻辑上。祝你好运，如果你需要什么，请告诉我

#include "math.h"
#include <iostream>
#include <limits>

using namespace std;

int loanAmount; //amount of the loan
double loanInterest; // the loan interest rate
int loanYears; //years of the loan
int loanTerm = loanYears; //loan term in months
double loanPay; //variable for outputting the payment

void cFunc();

int main()
{
cout<<"Enter Loan Amount";
cin>>loanAmount;
cFunc();
cout<<"Enter Loan Interest";
cin>>loanInterest;
cFunc();
cout<<"Enter Loan Years";
cin>>loanYears;
cFunc();


loanPay = (loanAmount * loanInterest) / (1 - pow(1+loanInterest,-loanYears)); //Formula to figure mortgage payment amount

cout<< "Your Monthly Payment Amount is: $"<< loanPay; //prints out monthly payment amount
return 0;
}

void cFunc(){
    cout << "Enter an int: ";
    int x = 0;
    while(!(cin >> x)){
        cin.clear();
        cin.ignore(numeric_limits<streamsize>::max(), '\n');
        cout << "Invalid input.  Try again: ";
    }
    cout << "You enterd: " << x << endl;
    // Why have a return int a function declared void?
    // return x;
}

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