结合 for 和 while 循环 (Java)

Question

我是 Java 新手，我正在尝试制作一个允许用户输入 100 个数字的程序，如果用户输入“0”，那么该程序假定打印最小、最大、总和等等号码。我得到了所有的工作，但没有退出并全部打印出来。我的老师说了一些关于使用while循环的事情，但是当你有一个for循环时怎么可能呢？

问候

public static void main(String[] args) {
    int[] list = new int[100];
    int min = 0;
    int max = 0;
    int sum = 0;
    boolean first = true;

    Scanner scan = new Scanner(System.in);
    while(list[i] != 0) {
        for (int i = 0; i < list.length; i++) {

            System.out.print("Enter number (0 to exit) " + (1 + i) + ":");
            list[i] = scan.nextInt();
        }

        for (int i = 0; i < list.length; i++) {

            if (first == true) {

            min = list[i];
            first = false;
        }

        if (list[i] < min) {

            min = list[i];
        }

        else if (list[i] > max) {

            max = list[i];
        }

        sum = list[i] + sum;

    }

    if (list[i] == 0) {

    System.out.print("Numbers are: " + list[0] + ", ");

    for (int i = 1; i < list.length; i++)

    System.out.print(list[i] + ", ");
    System.out.println();

    System.out.println("Smallest number is: " + min);
    System.out.println("Largest numeber is: " + min);
    System.out.println("Sum is: " + sum);
    }
    }
}

}

Answer 1

您只需要一个 while 循环来执行此操作，如果需要，还需要一个 for 循环来打印数组：

Scanner scan = new Scanner(System.in);
int i = 0;
int sum = 0;
int maxValue = Integer.MIN_VALUE;
int[] history = new int[100];
System.out.println("INPUT:");
int option = scan.nextInt();
while (option != 0 && i <= 100)
{
    if (option > maxValue)
        maxValue=option;
    sum += option;
    history[i] = option;
    option = scan.nextInt();
    i++;
}
System.out.println("OUTPUT: \n" + "SUM: " + sum + "\n MAX VALUE: " + maxValue);
for (int x : history)
    System.out.print(x + "");

Answer 2

这是方法的主体，它将按照您的要求执行。我没有使用过while循环（但实际上，for循环在内部是一种while循环）。

int size = 100; // Set the number of numbers to input.
int[] list = new int[size]; // Create an array with 'size' elements.
int min = Integer.MAX_VALUE; // Set the highest possible integer as start value.
int max = 0; // Set the minimum to zero, assuming that the user won't input negative numbers.
int sum = 0; // Initialize the sum of the numbers in the list.

Scanner scan = new Scanner(System.in);

for (int i = 0; i < size; i++) { // Run 'size' times the process of inputting a number.
    System.out.print("Enter number (0 to exit) " + (i + 1) + ": ");
    int number = scan.nextInt();
    if (number == 0) { // Quit program if input equals '0'
        System.out.println("Exiting...");
        break;
    }
    list[i] = number; // Add the current number to the list
    sum += number; // Add the number to the total
    if (number < min) { // If the number is smaller than the previous one, set this number as the smallest
        min = number;
    }
    if (number > max) { // If the number is greater than the previous smallest number, set this number as the greatest
        max = number;
    }
}

// Output all numbers in the list
for (int i = 0; i < list.length; i++) {
    if (list[i] != 0) {
        System.out.print((i == 0 ? "" : ", ") + list[i]);
    }
}

// You see the snippet (i == 0 ? "" : ", ")
// That is a shorthand if-else statement:
// If i equals 0, then "" (empty string), else ", " (comma and space).
// The statement
//     System.out.print((i == 0 ? "" : ", ") + list[i])
// is the same as
//     if (i == 0) {
//         System.out.println("") + list[i];
//     }
//     else {
//         System.out.println(", ") + list[i];
//     }

System.out.println("Smallest number is: " + min);
System.out.println("Largest numeber is: " + max);
System.out.println("Sum is: " + sum);

Answer 3

您的代码混乱。最好使用这样的模式：

while (true) {
    // read next
    if (input == 0) 
        break;
}