Question

我觉得这里有太多if语句，有没有办法进一步简化它？我确实减少了一点，但也许有一个更有效的解决方案？提前谢谢！

Scanner enterPrice = new Scanner(System.in);
double budgetRemaining = 100, itemPrice;

while (budgetRemaining > 0) {
    System.out.println("You have a remaining budget of $" + budgetRemaining + ". Please enter price of item:");
    System.out.println(itemPrice = enterPrice.nextDouble());

    if (itemPrice < budgetRemaining) {
        budgetRemaining -= itemPrice;

        if (itemPrice < 0) {
            budgetRemaining += itemPrice;
            System.out.println("Sorry, you have entered an invalid amount. ");
        }
    }
    else if (itemPrice > budgetRemaining) {
        System.out.println("Sorry, your item exceeds your budget.");
    }

    if (itemPrice == budgetRemaining) {
        budgetRemaining = 0;
        System.out.println("You have reached your maximum budget. Thank you for shopping with us!");
    }
}

Answer 1

移动否定价格检查

将第itemPrice < 0块中的if检出。该错误检查应该出现在所有代码路径上，而不仅仅是第一个。在从预算中减去之前检查负价格将使您不必将其重新添加。

while (budgetRemaining > 0) {
    System.out.println("You have a remaining budget of $" + budgetRemaining + ". Please enter price of item:");
    itemPrice = enterPrice.nextDouble();

    if (itemPrice < 0) {
        System.out.println("Sorry, you have entered an invalid amount. ");
        continue;
    }

    ...
}

合并案例

然后我会合并<和==个案例。保持逻辑尽可能相似：始终减去itemPrice。唯一的区别是你完成后打印一条消息。由于您有一个循环条件检查，您可以在循环外移动最终打印输出并完全删除if (itemPrice == budgetRemaining)检查。

while (budgetRemaining > 0) {
    System.out.println("You have a remaining budget of $" + budgetRemaining + ". Please enter price of item:");
    itemPrice = enterPrice.nextDouble();

    if (itemPrice < 0) {
        System.out.println("Sorry, you have entered an invalid amount. ");
        continue;
    }

    if (itemPrice <= budgetRemaining) {
        budgetRemaining -= itemPrice;
    }
    else if (itemPrice > budgetRemaining) {
        System.out.println("Sorry, your item exceeds your budget.");
    }
}

System.out.println("You have reached your maximum budget. Thank you for shopping with us!");

删除多余的else if

由于if和else if检查现在是完全相反的，因此第二个检查可以变为简单的else。

if (itemPrice <= budgetRemaining) {
    budgetRemaining -= itemPrice;
}
else {
    System.out.println("Sorry, your item exceeds your budget.");
}

提前退出

除此之外，我会切换订单，以便您先检查是否超出预算。由于我们预先检查itemPrice < 0，因此预先检查此其他错误情况也是有意义的。

while (budgetRemaining > 0) {
    System.out.println("You have a remaining budget of $" + budgetRemaining + ". Please enter price of item:");
    itemPrice = enterPrice.nextDouble();

    if (itemPrice < 0) {
        System.out.println("Sorry, you have entered an invalid amount. ");
        continue;
    }

    if (itemPrice > budgetRemaining) {
        System.out.println("Sorry, your item exceeds your budget.");
        continue;
    }

    budgetRemaining -= itemPrice;
}

System.out.println("You have reached your maximum budget. Thank you for shopping with us!");

这种错误检查方式+早期退出continue可以很容易地看出常规情况：budgetRemaining -= itemPrice语句现在位于任何条件之外。它已被提升为主代码路径。很明显，其他检查和打印输出是先决条件。

或者，您可以使用if / else链来编写此代码。两个都有效。现在只是风格偏好。

if (itemPrice < 0) {
    System.out.println("Sorry, you have entered an invalid amount. ");
}
else if (itemPrice > budgetRemaining) {
    System.out.println("Sorry, your item exceeds your budget.");
}
else {
    budgetRemaining -= itemPrice;
}

Answer 2

您可以先检查所有负面情况，然后再进一步简化。

Scanner enterPrice = new Scanner(System.in);
    double budgetRemaining = 100, itemPrice;
    while (budgetRemaining > 0) {
        System.out.println("You have a remaining budget of $" + budgetRemaining + ". Please enter price of item:");
        System.out.println(itemPrice = enterPrice.nextDouble());
        if (itemPrice < 0) {
            System.out.println("Sorry, you have entered an invalid amount. ");
        } else if (itemPrice > budgetRemaining) {
            System.out.println("Sorry, your item exceeds your budget.");
        } else if (itemPrice == budgetRemaining) {
            budgetRemaining = 0;
            System.out.println("You have reached your maximum budget. Thank you for shopping with us!");
        } else {
            budgetRemaining -= itemPrice;
        }
    }    
}

Answer 3

这是我的代码

while (budgetRemaining > 0) {
        System.out.println("You have a remaining budget of $" + budgetRemaining + ". Please enter price of item:");
        itemPrice = enterPrice.nextDouble();

        if (itemPrice < 1){
            System.out.println("Sorry, you have entered an invalid amount. ");
        }
        else if (itemPrice > budgetRemaining) {
            System.out.println("Sorry, your item exceeds your budget.");
        }
        else{
            budgetRemaining -= itemPrice;
        }
    }    
System.out.println("You have reached your maximum budget. Thank you for shopping with us!");

我在从预算中删除项目的值之前检查条件是否为真。如果我知道itemPrice有效：我只进行减法。

此外，当您退出货币时，while循环将自动退出，因此无需在实际退出前检查余额。你不妨打印一下这句话。

我做的另一件小事是设置itemPice＆lt; 1，因为我认为该项目不能完全免费。

有没有进一步的方法来简化这段代码？

3 个答案: