如何优化这段C++代码避免重复逻辑，并处理输入异常？

Let's break this down into two main parts: fixing that annoying input error, and cleaning up duplicated logic to make your code easier to work with.

1. Squashing the Input Exception #

The crash happens because when you prompt for an upgrade option after typing "upgrade", you're using cin >> upgr to read an integer. If the user enters anything that's not a number (like "abc" or even "2"), here's what goes wrong:

• cin enters a failed state because it can't parse non-numeric input into an integer.
• After that, all future cin calls will skip execution entirely, making your program loop without responding to input.

Here's how to fix it:

• Always check if cin succeeded after reading input.
• If it fails, reset the error flag and clear out the invalid input from the buffer.
• Add a fallback message for when the user enters a valid number that's not 1.

2. Cutting Out Repetitive Logic #

Your code repeats power*3 multiple times (calculating tapcost, checking if money is enough). This is a problem because if you ever want to change the cost formula (like making it power*4), you'd have to update it in every spot. Instead:

• Calculate the upgrade cost once and store it in a variable (you already have tapcost, let's use it consistently).
• Use else if instead of separate if statements for way checks—this avoids unnecessary checks once a match is found.

Refactored Full Code #

#include <iostream>
#include <string>
#include <limits> // For clearing invalid input

using namespace std;

int main() {
    int power = 1;
    int money = 0; // Added initialization (you likely missed this in your original code)
    string way;
    int upgr;

    while (true) { // More readable than "1 == 1"
        int upgradeCost = power * 3; // Calculate once, reuse everywhere

        cout << "Type upgrade/buy/a" << endl;
        cin >> way;

        if (way == "upgrade") {
            cout << "1. A Power (Costs: " << upgradeCost << ")" << endl;
            
            // Check if input reading succeeded
            if (!(cin >> upgr)) {
                cout << "Please enter a valid number!" << endl;
                cin.clear(); // Reset cin's error state
                // Clear all invalid input from the buffer
                cin.ignore(numeric_limits<streamsize>::max(), '\n');
                continue; // Skip to next loop iteration
            }

            if (upgr == 1) {
                if (money >= upgradeCost) {
                    power++;
                    money -= upgradeCost;
                    cout << "Power upgraded! New power: " << power << endl;
                } else {
                    cout << "You can't afford that!!!" << endl;
                }
            } else {
                cout << "Invalid option! Please enter 1 to upgrade." << endl;
            }
        } 
        else if (way == "a") {
            money += power;
            cout << "Money increased! Current money: " << money << endl;
        }
        else if (way == "buy") {
            // You included this in the prompt but had no logic—add your buy code here!
            cout << "Buy functionality not implemented yet." << endl;
        }
        else {
            cout << "Invalid command! Please type upgrade/buy/a." << endl;
        }
    }

    return 0;
}

Key Improvements: #

• Input Safety: Added checks for non-numeric input, resets cin state, and clears invalid input to prevent crashes.
• No Duplication: upgradeCost is calculated once and reused, so changing the cost formula only needs one edit.
• Readability: Replaced 1 == 1 with true, added else if chains, and added clear feedback for all invalid inputs.
• Uninitialized Variables: Fixed missing money initialization (a common oversight that could cause weird behavior).

内容的提问来源于stack exchange，提问作者Alpha Reaper