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Thread: Homework problem (scanner problems)

  1. #1
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    Default Homework problem (scanner problems)

    I'm supposed to create a program that Asks for 3 names, as well as their age. It should ask one name, then their age, then the next and so on. When I compile this program, here is what happens.

    Enter the persons name:
    Tom
    Enter the persons age
    20
    Enter the persons name:
    Enter the persons age
    Tom
    Exception in thread "main" java.util.InputMismatchException
    at java.util.Scanner.throwFor(Unknown Source)
    at java.util.Scanner.next(Unknown Source)
    at java.util.Scanner.nextInt(Unknown Source)
    at java.util.Scanner.nextInt(Unknown Source)
    at Oldest.main(Oldest.java:17)
    Enter name shows up, I enter the name, enter age shows up, I enter the age, then the next set comes up together (Enter name, Enter age, without giving me a chance to enter a name before enter age pops up). The rest is the error message

    import java.util.*;
    public class Oldest {
    public static void main(String[] args) {
    	Scanner stdin = new Scanner(System.in);
    	String per1name, per2name, per3name;
    	int per1age, per2age, per3age;
     
    	System.out.println("Enter the persons name: ");
    	per1name = stdin.nextLine();
    	System.out.println("Enter the persons age");
    	per1age = stdin.nextInt();
    	System.out.println("Enter the persons name: ");
    	per2name = stdin.nextLine();
    	System.out.println("Enter the persons age");
    	per2age = stdin.nextInt();
    	System.out.println("Enter the persons name: ");
    	per3name = stdin.nextLine();
    	System.out.println("Enter the persons age");
    	per3age = stdin.nextInt();
     
    	if((per1age > per2age) && (per1age > per3age)){
    		System.out.println(per1name + " is the oldest person with the age " + per1age);
    	}else if((per2age > per1age) && (per2age > per3age)){
    		System.out.println(per2name + " is the oldest person with the age " + per2age);
    	}else
    		System.out.println(per3name + " is the oldest person with the age " + per3age);
    }
    }


  2. #2
    Super Moderator helloworld922's Avatar
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    Default Re: Homework problem (scanner problems)

    It's because nextInt() doesn't consume the newline character in the input stream. Try this:
    import java.util.*;
    public class Oldest {
    public static void main(String[] args) {
    	Scanner stdin = new Scanner(System.in);
    	String per1name, per2name, per3name;
    	int per1age, per2age, per3age;
     
    	System.out.println("Enter the persons name: ");
    	per1name = stdin.nextLine();
    	System.out.println("Enter the persons age");
    	per1age = stdin.nextInt();
            stdin.nextLine();
    	System.out.println("Enter the persons name: ");
    	per2name = stdin.nextLine();
    	System.out.println("Enter the persons age");
    	per2age = stdin.nextInt();
            stdin.nextLine();
    	System.out.println("Enter the persons name: ");
    	per3name = stdin.nextLine();
    	System.out.println("Enter the persons age");
    	per3age = stdin.nextInt();
            stdin.nextLine();
     
    	if((per1age > per2age) && (per1age > per3age)){
    		System.out.println(per1name + " is the oldest person with the age " + per1age);
    	}else if((per2age > per1age) && (per2age > per3age)){
    		System.out.println(per2name + " is the oldest person with the age " + per2age);
    	}else
    		System.out.println(per3name + " is the oldest person with the age " + per3age);
    }
    }

  3. The Following User Says Thank You to helloworld922 For This Useful Post:

    TommyFiz (September 20th, 2009)

  4. #3
    Junior Member
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    Default Re: Homework problem (scanner problems)

    Awesome that worked. Thanks for the fast reply!

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