Question

我必须编写一个程序，该程序首先请求范围为0

import java.util.*;
class ExamTesterNine{
  public static void main(String args[]){
   Scanner kbReader= new Scanner(System.in);
   int num=kbReader.nextInt();
   System.out.println("Enter an integer smaller than 20 and larger than 0");
   int result;
   int sum=0;

   if (!(num>0&&num<20)){
     return;
   }else{
     for(int i=1; i<=num; i++)
   sum=sum+i;

   int [] number= new int [num];
   for (int a=0; a<(number.length-1); a++ ){
     number[a]=a+1;
     System.out.print(number[a]+"+");}
   System.out.print(num+"="+sum);
   }

  }
}

Answer 1

使用do-while使IT变得容易。我现在不在编译器上，但是如果使用扫描仪，则应该在代码中添加

import java.util.*;
class ExamTesterNine{
public static void main(String args[]){
Scanner kbReader= new Scanner(System.in);
int num = 0;
System.out.println("Enter an integer smaller than 20 and larger than 0");
  do{
     num=kbReader.nextInt();
   } while(num<0 && num <20);

   int result;
   int sum=0;

   for(int i=1; i<=num; i++)
   sum=sum+i;

   int [] number= new int [num];
   for (int a=0; a<(number.length-1); a++ ){
     number[a]=a+1;
     System.out.print(number[a]+"+");}
   System.out.print(num+"="+sum);
   }

  }
}

让我知道是否可以快速进入编译器，但是do-while是您的解决方案。

Answer 2

您将需要一个while循环，因为您不知道输入了多少次错误的输入

while (true) {
  System.out.println("Enter an integer smaller than 20 and larger than 0");
  int num=kbReader.nextInt(); // get input
  // test
  if (goodInput (num)) {
      break;
  }
}

Answer 3

要获取电话号码，请尝试使用像这样的支票

int number=0;
boolean flag;
while{
    flag=false;
    System.out.println("Enter a number smaller than 20 and greater than 0 : ");
    try{          
        number=kbReader.nextInt();
        flag=true;
    }catch(Exception e){ //catching the exception that occurs when an input other than integer is entered
        System.out.println("OOPS!!!only Integer is allowed :-("); 
    }
    if(flag==true && number>0 && number<20){
        break;
    }else{
        if(flag){
        System.out.println("Oops!!!only numbers in the range 0<number<20 is allowed...Re-enter again");
        }
    }

Answer 4

有许多不同的方法可以解决此问题。但是，为了开始熟悉while循环，我建议您使用以下简单方法：

System.out.println("Enter an integer smaller than 20 and larger than 0");
int num = kbReader.nextInt();

while(num > 20 || num < 0)
{
    System.out.println("That value does not meet the criteria. Please try again:");
    num = kbReader.nextInt();
}

在输入正确值之前，将要求用户重试输入。

Answer 5

import java.util.*;
class ExamTesterNine{
static int num;
public static void readInput() {
     System.out.println("Enter an integer smaller than 20 and larger than 0");
       Scanner kbReader= new Scanner(System.in);
       num=kbReader.nextInt();
       if (!(num>0&&num<20)){
           ExamTesterNine.readInput();
       }else {
           calculate(num); 
       }
   }
public static void calculate(int sum) {
    for(int i=1; i<=num; i++)
           sum=sum+i;
           int [] number= new int [num];
           for (int a=0; a<(number.length-1); a++ ){
             number[a]=a+1;
             System.out.print(number[a]+"+");}
           System.out.print(num+"="+sum);
}

  public static void main(String args[]){
  int result;
  int sum=0;
  ExamTesterNine.readInput();
    }
 }

 Are you expecting this?
  Out put:Enter an integer smaller than 20 and larger than 0
  23
  Enter an integer smaller than 20 and larger than 0
  34
  Enter an integer smaller than 20 and larger than 0
  56
  Enter an integer smaller than 20 and larger than 0
  45
  Enter an integer smaller than 20 and larger than 0
  15
  1+2+3+4+5+6+7+8+9+10+11+12+13+14+15=135

如何编写一个程序，该程序可以不断要求用户输入，直到输入满足运行代码的特定要求？

5 个答案: