How Can I Ensure My Java Program Accepts Only Valid Integer Input Using Scanner?

Accepting Only Valid Integer Input with Scanner

When developing robust Java programs, it is crucial to handle invalid user inputs to ensure stability. One common challenge involves accepting numeric input and preventing the program from crashing due to invalid characters.

To address this, you can utilize the Scanner.hasNextInt() method, which verifies if the next token in the input can be interpreted as an integer. Here's how you can implement it:

Scanner sc = new Scanner(System.in);
System.out.print("Enter number 1: ");
while (!sc.hasNextInt()) sc.next();
int num1 = sc.nextInt();

This code loops until a valid integer is entered, skipping over any invalid characters. You can apply the same logic to accept number 2 and ensure it is greater than number 1:

int num2;
System.out.print("Enter number 2: ");
do {
    while (!sc.hasNextInt()) sc.next();
    num2 = sc.nextInt();
} while (num2 < num1);

By incorporating these techniques, you can effectively prevent the program from crashing due to invalid inputs and ensure that only valid integer values are accepted, enhancing the robustness of your application.

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