c++ - 在“while”循环中清除累加器

Question

这段代码需要做 4 件事：

• 输入销售商品数量
• 输入每个销售项目的价格
• 输入税率
• 再次运行的选项

我已经完成了所有这些要求，但是当代码重复时，我唯一的问题出现了。我将总项目值保存在“while”后测试循环中的累加器中。当程序循环时，它不会清除累加器，而是继续在我的旧总值之上添加任何新值。

（例如，如果我第一次运行代码总共有 20 美元，而重复运行总共有 30 美元，它将显示我的总价格为 50 美元）

#include <iostream>
#include <iomanip>
using namespace std;

int main(){

char answer = ' ';
int saleItems = 0;
double itemValue = 0.0;
double titemValue = 0.0;
double taxPerc = 0.0;

do {
    cout << "How many sales items do you have? : ";
    cin >> saleItems;

    for (int x = 1; x <= saleItems; x += 1){
        cout << "Enter in the value of sales item " << x << " : $";
        cin >> itemValue;
        titemValue += itemValue;
    } 

    cout << endl << endl;
    cout << "Enter in the sales tax percentage(Enter 10 for 10%): ";
    cin >> taxPerc;
    cout << endl << endl;

    double saleTax = titemValue * (taxPerc / 100);
    double grandTotal = titemValue + saleTax;

    cout << fixed << setprecision(2);

    cout << "********************************************" << endl;
    cout << "********  S A L E S  R E C E I P T  ********" << endl;
    cout << "********************************************" << endl;
    cout << "**                                        **" << endl;
    cout << "**                                        **" << endl;
    cout << "**                                        **" << endl;
    cout << "**                                        **" << endl;
    cout << "**  Total Sales            $" << setw(9) << titemValue << "     **" << endl;
    cout << "**  Sales Tax              $" << setw(9) << saleTax << "     **" << endl;
    cout << "**                          ----------    **" << endl;
    cout << "**  Grand Total            $" << setw(9) << grandTotal << "     **" << endl;
    cout << "**                                        **" << endl;
    cout << "**                                        **" << endl;
    cout << "********************************************" << endl << endl << endl;

    cout << "Do you want to run this program again? (Y/N):";
    cin >> answer;
    answer = toupper(answer);
    cout << endl << endl;

    } while (answer == 'Y');


return 0;
}

Answer 1

您需要在循环内重置 titemValue 的值，但它是在循环外设置的。改变

char answer = ' ';
int saleItems = 0;
double itemValue = 0.0;
double titemValue = 0.0;
double taxPerc = 0.0;

do {
    cout << "How many sales items do you have? : ";
    cin >> saleItems;

到

char answer = ' ';
int saleItems = 0;
double itemValue = 0.0;
double titemValue; // (changed)
double taxPerc = 0.0;

do {
    titemValue = 0.0; // (new)
    cout << "How many sales items do you have? : ";
    cin >> saleItems;

您不一定需要更改第一行，但将其值设置为相同的东西两次是没有意义的。不过，AFAIK 一些编译器可能会优化它，如果你仍然保留双重初始化。有些不会，比如 Visual Studio 中默认的 Debug 配置设置。