How to Convert A String to an Integer In Java?

To convert a string to an integer in Java, you can use the parseInt() method of the Integer class. This method takes a string as an argument and returns an integer value. Here's an example of how you can convert a string to an integer:

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String str = "123";
int num = Integer.parseInt(str);
System.out.println(num); // Output: 123

Make sure that the string you are trying to convert is a valid integer value, otherwise it will throw a NumberFormatException.

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What is the purpose of using try-catch block when converting a string to an integer in Java?

The purpose of using a try-catch block when converting a string to an integer in Java is to handle any exceptions that may occur during the conversion process. For example, if the string does not represent a valid integer or if there is an error during the conversion, a NumberFormatException will be thrown. By using a try-catch block, we can catch this exception and handle it gracefully, such as displaying an error message to the user or providing a default value instead. This helps prevent the program from crashing and allows for more robust error handling.

What is the type of exception thrown when converting a string to an integer in Java fails?

NumberFormatException

How to convert a string to an integer in Java using Scanner class?

To convert a string to an integer in Java using the Scanner class, you can follow these steps:

1. Import the Scanner class at the beginning of your program:

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import java.util.Scanner;

1. Create a Scanner object to read input from the user:

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Scanner scanner = new Scanner(System.in);

1. Prompt the user to enter a string and store it in a variable:

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System.out.print("Enter a number: ");
String input = scanner.next();

1. Use the Integer.parseInt() method to convert the string to an integer:

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int number = Integer.parseInt(input);

1. Print out the integer value:

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System.out.println("The integer value is: " + number);

1. Remember to close the Scanner object at the end of your program to free up system resources:

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scanner.close();

Here is the complete code snippet:

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import java.util.Scanner;

public class StringToInteger {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        
        System.out.print("Enter a number: ");
        String input = scanner.next();
        
        int number = Integer.parseInt(input);
        
        System.out.println("The integer value is: " + number);
        
        scanner.close();
    }
}

When you run this program and enter a string that represents a valid integer, it will convert the string to an integer and display the result.