如何用循环替代C++披萨店程序中的多个if语句？

我正在初学者编程课程中编写一个披萨店场景的C++基础程序，需求如下：

• 根据预算询问用户是否需要额外披萨配料
• 若用户选择是，则更新预算（Budget）和账单（Invoice）
• 展示所选披萨配料的汇总
• 展示最终账单和剩余金额

目前我用多个if语句输出所选配料：

cout << "\nHere is a summary of your order: \n" ;

if (Olives2 == true){
    cout << "-Olives\n";
}

if (Onions2 == true){
    cout << "-Onions\n";
}

if (Cheese2 == true){
    cout << "-Cheese\n" ;
}

if (Salami2 == true){
    cout << "-Salami\n";
}

if (Shrimps2 == true){
    cout << "-Shrimps\n\n";
}

这些布尔变量（如Cheese2）通过switch语句更新，示例如下：

if (Budget >= Shrimps1 ) {
    cout << "Any Shrimp? y/n ";
    cin >> Toppings;

    switch (Toppings) {
        case 'y':
            Invoice = Invoice + Shrimps1;
            Budget = 100 - Invoice;
            cout << "Your subtotal is R" << Invoice << ", with a remainder of R" << Budget << endl;
            Shrimps2 = true;
            break;

        case 'n':
            cout << "Your subtotal is R" << Invoice << ", with a remainder of R" << Budget << endl;
            break;
    }
}

请问是否可以用循环替代这些if语句，让代码更简洁？

当然可以用循环替代重复的if语句，核心是把配料的名称、价格、选中状态打包成统一的数据结构，用容器存储后遍历处理，既能精简代码，还能大幅提升扩展性。

1. 定义配料数据结构 #

用结构体把配料的相关信息绑定在一起，替代原来零散的独立变量：

#include <iostream>
#include <vector>

using namespace std;

struct Topping {
    string name;   // 配料名称
    int price;     // 配料价格
    bool selected; // 是否被选中
};

2. 初始化配料列表 #

把所有配料信息存入vector，后续新增配料只需在列表里添加一行即可：

int main() {
    int budget = 100;
    int invoice = 0;

    vector<Topping> toppings = {
        {"Olives", 10, false},
        {"Onions", 8, false},
        {"Cheese", 12, false},
        {"Salami", 15, false},
        {"Shrimps", 20, false}
    };

3. 用循环替代重复的switch逻辑 #

遍历配料列表，逐个询问用户需求，同时更新预算和选中状态：

char choice;
    for (auto &topping : toppings) {
        if (budget >= topping.price) {
            cout << "Any " << topping.name << "? y/n ";
            cin >> choice;

            if (choice == 'y') {
                invoice += topping.price;
                budget -= topping.price;
                topping.selected = true;
            }
            cout << "Your subtotal is R" << invoice << ", with a remainder of R" << budget << endl;
        } else {
            cout << "Not enough budget for " << topping.name << endl;
        }
    }

4. 用循环替代多个if输出汇总 #

遍历配料列表，只打印用户选中的配料：

cout << "\nHere is a summary of your order: \n";
    for (const auto &topping : toppings) {
        if (topping.selected) {
            cout << "-" << topping.name << "\n";
        }
    }
    cout << "\nFinal Invoice: R" << invoice << "\nRemaining Budget: R" << budget << endl;

    return 0;
}

优化后的优势 #

• 扩展性强：新增配料不用修改逻辑代码，只需在配料列表里添加一行数据
• 代码简洁：消除了大量重复的if和switch语句，可读性和维护性大幅提升
• 逻辑更严谨：直接用budget -= topping.price更新预算，避免原代码中固定100的硬编码问题

内容的提问来源于stack exchange，提问作者Corne