我已经用这段代码完成了很多工作,除了我需要用户在宇宙边界内输入数字之外,它几乎可以正确运行。我确保用户只能输入整数。但是我不确定如何确保数字为1-10(已设置Universe)。有人可以给我一些指导吗?
这是我的代码:
import java.util.*;
public class sets {
public static void main (String[] args) {
Scanner in = new Scanner(System.in);
//declare the universe in a set
Set universe = new HashSet();
for (int i = 1; i <= 10; i++) {
universe.add(i);
}
//Ask the user how many elements and declare set A
System.out.print("How many elements in Set A? ");
int elementsA = in.nextInt();
Set A = new HashSet();
for (int j = 1; j <= elementsA; j++) {
System.out.print("Enter a number 1-10: ");
while (!in.hasNextInt()) {
in.next();
System.out.println("Input must be a number.");
System.out.print("Enter a number 1-10: ");
}
int numA = in.nextInt();
A.add(numA);
}
//Ask the user how many elements and declare set B
System.out.print("How many elements in Set B? ");
int elementsB = in.nextInt();
Set B = new HashSet();
for (int k = 1; k <= elementsB; k++) {
System.out.print("Enter a number 1-10: ");
while (!in.hasNextInt()) {
in.next();
System.out.println("Input must be a number.");
System.out.print("Enter a number 1-10: ");
}
int numB = in.nextInt();
B.add(numB);
}
//get the union of the sets
Set union = new HashSet(A);
union.addAll(B);
System.out.println("The union of A and B: "+union);
//get the intersection of the sets
Set intersect = new HashSet(A);
intersect.retainAll(B);
System.out.println("The intersection of A and B: "+intersect);
}
}
最佳答案
就像是
while (!in.hasNextInt()) {
in.next();
System.out.println("Input must be a number.");
}
int numA = in.nextInt();
while (numA < 0 || numA > 10) {
System.out.print("Enter a number 1-10: ");
numA = in.nextInt();
}
A.add(numA);
编辑:考虑到上述情况,我将加强解决方案,如下所示
while (true) {
if (!in.hasNextInt()) {
System.out.println("Input must be a number.");
in.next();
} else {
int num = in.nextInt();
if (num < 0 || num > 10) {
System.out.println("Input must be between 1 and 10 (inclusive).");
} else {
// add num to collection
break;
}
}
}
关于java - 使用集处理用户错误,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/21711620/