java - 负输入的验证

Question

我正在尝试验证用户输入。我不希望用户输入负数、字符串和 double 。我只需要 int。我只能验证字符串和 double 。我们将不胜感激您的帮助。

do {

    System.out.println("How many cappuccino drinks were sold today?");
    if(input.hasNextInt()) {

        cappuccinoDrink = input.nextInt();


            capexpenses = cappuccinoDrink * 1.56;
            capRevenue = cappuccinoDrink * 3.50;
            capProfit = capRevenue - capexpenses;
            isNumber = true;

    }else {
        System.out.println("You didn't didn't enter the require imput");
        isNumber = false;
        input.next();
    }
} while(!isNumber);

Answer 1

将 if(input.hasNextInt()) { 更改为以下内容:

if(input.hasNextInt() && (cappuccinoDrink = input.nextInt()) >= 0) {
            //removed assignment as it is handled in if statement
            capRevenue = cappuccinoDrink * 3.50;
            capProfit = capRevenue - capexpenses;
            isNumber = true;
}