使用扫描程序接受字符串输入并存储在字符串数组中

Question

Can someone help me please. I have done numerous searches but can't find a solution anywhere. I'm a beginner to Java and currently practicing some code while on a break from college.

I am trying to make a Phonebook program. At the moment I am trying to add a new contact, below is the code i have but i am not sure how to store the information in an array can someone give me some pointers please.

    import java.util.Scanner;

    public class addContact {
    public static void main(String [] args){

    //declare arrays
        String [] contactName = new String [12];
        String [] contactPhone = new String [12];
        String [] contactAdd1 = new String [12];
        String [] contactAdd2 = new String [12];

    //inputs
    String name = "";
    String phone = "";
    String add1 = "";
    String add2 = "";

    //method of taken input
    Scanner input = new Scanner(System.in);

    //while name field is empty display prompt etc.
    while (name.equals(""))
    {
    System.out.println("Enter contacts name: ");
    name = input.nextLine();
    name += contactName[];
    }


    while (add1.equals(""))
    {
    System.out.println("Enter contacts addressline1:");
    add1 = input.nextLine();
    add1 += contactAdd1[];
    }

    while (add2.equals(""))
    {
    System.out.println("Enter contacts addressline2:");
    add2 = input.nextLine();
    add2 += contactAdd2[];
    }

    while (phone.equals(""))
    {
    System.out.println("Enter contact phone number: ");
    phone = input.nextLine();
    phone += contactPhone[];
    }

    }   
}

Answer 1

A cleaner approach would be to create a Person object that contains contactName , contactPhone , etc. Then, use an ArrayList rather then an array to add the new objects. Create a loop that accepts all the fields for each `Person:

while (!done) {
   Person person = new Person();
   String name = input.nextLine();
   person.setContactName(name);
   ...

   myPersonList.add(person);
}

Using the list will remove the need for array bounds checking.

Answer 2

One of the problem with this code is here :

name += contactName[];

This instruction won't insert anything in the array. Instead it will concatenate the current value of the variable name with the string representation of the contactName array.

Instead use this:

contactName[index] = name;

this instruction will store the variable name in the contactName array at the index index .

The second problem you have is that you don't have the variable index .

What you can do is a loop with 12 iterations to fill all your arrays. (and index will be your iteration variable)

Answer 3

//go through this code I have made several changes in it//

import java.util.Scanner;

public class addContact {
public static void main(String [] args){

//declare arrays
String [] contactName = new String [12];
String [] contactPhone = new String [12];
String [] contactAdd1 = new String [12];
String [] contactAdd2 = new String [12];
int i=0;
String name = "0";
String phone = "0";
String add1 = "0";
String add2 = "0";
//method of taken input
Scanner input = new Scanner(System.in);

//while name field is empty display prompt etc.
while (i<11)
{
    i++;
System.out.println("Enter contacts name: "+ i);
name = input.nextLine();
name += contactName[i];
}


while (i<12)
{
    i++;
System.out.println("Enter contacts addressline1:");
add1 = input.nextLine();
add1 += contactAdd1[i];
}

while (i<12)
{
    i++;
System.out.println("Enter contacts addressline2:");
add2 = input.nextLine();
add2 += contactAdd2[i];
}

while (i<12)
{
    i++;
System.out.println("Enter contact phone number: ");
phone = input.nextLine();
phone += contactPhone[i];
}

}   
}

Answer 4

Would this work better?

import java.util.Scanner;

public class Work {

public static void main(String[] args){

    System.out.println("Please enter the following information");

    String name = "0";
    String num = "0";
    String address = "0";

    int i = 0;

    Scanner input = new Scanner(System.in);

    //The Arrays
    String [] contactName = new String [7];
    String [] contactNum = new String [7];
    String [] contactAdd = new String [7];

    //I set these as the Array titles
    contactName[0] = "Name";
    contactNum[0] = "Phone Number";
    contactAdd[0] = "Address";

    //This asks for the information and builds an Array for each
    //i -= i resets i back to 0 so the arrays are not 7,14,21+
    while (i < 6){

        i++;
        System.out.println("Enter contact name." + i);
        name = input.nextLine();
        contactName[i] = name;
    }

    i -= i;
    while (i < 6){
        i++;
        System.out.println("Enter contact number." + i);
        num = input.nextLine();
        contactNum[i] = num;
    }

    i -= i;
    while (i < 6){
        i++;
        System.out.println("Enter contact address." + i);
        num = input.nextLine();
        contactAdd[i] = num;
    }


    //Now lets print out the Arrays
    i -= i;
    while(i < 6){
    i++;
    System.out.print( i + " " + contactName[i] + " / " );
    }

    //These are set to print the array on one line so println will skip a line
    System.out.println();
    i -= i;
    i -= 1;

    while(i < 6){
    i++;

    System.out.print( i + " " + contactNum[i] + " / " );
    }

    System.out.println();
    i -= i;
    i -= 1;

    while(i < 6){
        i++;

    System.out.print( i + " " + contactAdd[i] + " / " );
    }

    System.out.println();

    System.out.println("End of program");

}

}

Answer 5

Please correct me if I'm wrong.`

public static void main(String[] args) {

    Scanner na = new Scanner(System.in);
    System.out.println("Please enter the number of contacts: ");
    int num = na.nextInt();

    String[] contactName = new String[num];
    String[] contactPhone = new String[num];
    String[] contactAdd1 = new String[num];
    String[] contactAdd2 = new String[num];

    Scanner input = new Scanner(System.in);

    for (int i = 0; i < num; i++) {

        System.out.println("Enter contacts name: " + (i+1));
        contactName[i] = input.nextLine();

        System.out.println("Enter contacts addressline1: " + (i+1));
        contactAdd1[i] = input.nextLine();

        System.out.println("Enter contacts addressline2: " + (i+1));
        contactAdd2[i] = input.nextLine();

        System.out.println("Enter contact phone number: " + (i+1));
        contactPhone[i] = input.nextLine();

    }

    for (int i = 0; i < num; i++) {
        System.out.println("Contact Name No." + (i+1) + " is "+contactName[i]);
        System.out.println("First Contacts Address No." + (i+1) + " is "+contactAdd1[i]);
        System.out.println("Second Contacts Address No." + (i+1) + " is "+contactAdd2[i]);
        System.out.println("Contact Phone Number No." + (i+1) + " is "+contactPhone[i]);
    }
}

`

Answer 6

There is no use of pointers in java so far. You can create an object from the class and use different classes which are linked with each other and use the functions of every class in main class.