使用switch语句检查一个数的倍数

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英文:

Checking multiples of a number using a switch statement

问题

对于一个Java编程作业,我需要使用if/else语句和switch语句来判断一个数字n是否为2379的倍数。使用if/else很简单(例如 n % 7 == 0),但我似乎无法弄清楚如何使用switch语句实现这一点。

英文:

For a Java programming assignment, I am required to use both if/else and switch statements to display if a number n is a multiple of 2, 3, 7 or 9. Using an if/else is easy (e.g. n % 7 == 0), but I cannot seem to figure out how to implement this with a switch statement.

答案1

得分: 1

这是我能够的方式:

 int arr[] = {2, 3, 7, 9};

        for (int number:arr) {

            int input = 9;
            int result = input % number;

            switch (result) {
                case 0:
                    System.out.println(input + " 是 " + number + " 的倍数");
                    break;
                default:
                    System.out.println(input + " 不是 " + number + " 的倍数");

            }
        }
英文:

This is the way I can

 int arr[] = {2, 3, 7, 9};

        for (int number:arr) {

            int input = 9;
            int result = input % number;

            switch (result) {
                case 0:
                    System.out.println(input+" is multiple  of " + number);
                    break;
                default:
                    System.out.println(input+" is not multiple of " + number);

            }
        }
        

答案2

得分: 1

使用新的Java 14模式匹配语法的稍显荒谬的解决方案。

boolean isMultiple = switch (n % 2) {
    case 0 -> true;
    default -> switch (n % 3) {
        case 0 -> true;
        default -> switch (n % 7) {
            case 0 -> true;
            default -> false;
        };
    };
};
英文:

Mildly ridiculous solution using the new Java 14 pattern matching syntax.

	boolean isMultiple = switch (n % 2) {
		case 0 -> true;
		default -> switch (n % 3) {
			case 0 -> true;
			default -> switch (n % 7) {
				case 0 -> true;
				default -> false;
			};
		};
	};

答案3

得分: 0

请尝试这个。它简单地迭代嵌套的 switch 块,打印出相应的结果。

int[] candidates = { 10, 15, 19, 21, 6, 9 };
for (int candidate : candidates) {
    System.out.printf("%d 可以被以下数整除:", candidate);
    StringBuilder sb = new StringBuilder();
    switch (candidate % 2) {
        case 0:
            sb.append(2).append(" ");
        default:
            switch (candidate % 3) {
                case 0:
                    sb.append(3).append(" ");
                default:
                    switch (candidate % 7) {
                        case 0:
                            sb.append(7).append(" ");
                        default:
                            switch (candidate % 9) {
                                case 0:
                                    sb.append(9).append(" ");
                                default:
                            }
                    }
            }
    }
    System.out.println(sb.length() > 0 ? sb.toString() :
            "无法被以上数整除。");
}

输出结果:

10 可以被以下数整除:2 
15 可以被以下数整除:3 
19 无法被以上数整除。
21 可以被以下数整除:3 7 
6 可以被以下数整除:2 3 
9 可以被以下数整除:3 9 
英文:

Try this. It simply iterates over nested switch blocks printing the appropriate results.

int[] candidates = { 10, 15, 19, 21, 6, 9 };
for (int candidate : candidates) {
	System.out.printf("%d is divisible by ", candidate);
	StringBuilder sb = new StringBuilder();
	switch (candidate % 2) {
		case 0:
			sb.append(2).append(" ");
		default:
			switch (candidate % 3) {
				case 0:
					sb.append(3).append(" ");
				default:
					switch (candidate % 7) {
						case 0:
							sb.append(7).append(" ");
						default:
							switch (candidate % 9) {
								case 0:
									sb.append(9).append(" ");
								default:
							}
					}
			}
	}
	System.out.println(sb.length() > 0 ? sb.toString() :
			"none of the divisors.");
	
}

Prints

10 is divisible by 2 
15 is divisible by 3 
19 is divisible by none of the divisors.
21 is divisible by 3 7 
6 is divisible by 2 3 
9 is divisible by 3 9 


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  • 本文由 发表于 2020年10月6日 09:37:32
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