Java 编写一个程序来读取两个数字，第一个小于第二个。该程序将写入两个数字之间的所有数字
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原文地址: http://stackoverflow.com/questions/19528826/
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Write a program to read two numbers, the first less than the second. The program will write all numbers between the two numbers
提问by
//So I wrote this: (the output down there)
//所以我写了这个：（输出在那里）
import java.util.Scanner;
public class E7L6{
public static void main(String[]args){
int num1, num2;
Scanner keyboard= new Scanner(System.in);
System.out.print("Type two numbers:");
num1= keyboard.nextInt();
num2= keyboard.nextInt();
if(num1<num2){
while(num1<=num2){
int counter=num1;
System.out.print(counter+" "+num2);
counter=counter+1;
}}
else{
System.out.print("Error: the first number must be smaller than the second");
}
}}
Output:
----jGRASP exec: java E7L6
Type two numbers:4 124
4 4 4 4 4 4 4 4 4
----jGRASP: process ended by user.
//so many number 4 repeating can someone tell me where am i wrong? thanks!!
//这么多重复的数字4有人能告诉我我错在哪里了吗？谢谢！！
采纳答案by Reji
while(num1<=num2){
int counter=num1;
System.out.print(counter+" "+num2);
counter=counter+1;
}
This will end up in infinite loop. The condition for the while loop needs to be modified.
这将最终陷入无限循环。需要修改 while 循环的条件。
// modified code - Complete code.
// 修改后的代码 - 完整的代码。
import java.util.Scanner;
public class E7L6 {
public static void main(String[] args) {
int num1, num2;
Scanner keyboard = new Scanner(System.in);
System.out.print("Type two numbers:");
num1 = keyboard.nextInt();
num2 = keyboard.nextInt();
if (num1 < num2) {
int counter = num1;
while (counter <= num2) {
System.out.print(counter + " ");
counter = counter + 1;
}
} else {
System.out
.print("Error: the first number must be smaller than the second");
}
}
}
回答by SLaks
int counter=num1;
You created a new countervariable for each iteration of the loop.
Therefore, they all have the same value.
您counter为循环的每次迭代创建了一个新变量。
因此，它们都具有相同的值。
It runs forever because your loop condition can never be false (you never change num1or num2).
它永远运行，因为您的循环条件永远不会为假（您永远不会改变num1或num2）。
回答by Kai
As a novice programmer I would use for loop instead. It would be simpler and easier:
作为新手程序员，我会改用 for 循环。它会更简单，更容易：
for(ctr=num1;ctr<=num2;ctr++)
s.o.p(ctr)
回答by Dvoryanin25
Here you go:
干得好：
System.out.print("First:");
int first = Integer.parseInt(reader.nextLine());
System.out.print("Second:");
int second = Integer.parseInt(reader.nextLine());
while (first <= second) {
System.out.println(first);
first++;
}
