I'm trying to create a program that guesses the user's age and I'm having some trouble. Here is my code:

System.out.println("Let me guess your age.");
System.out.println("Enter remainders of dividing your age by 3, 5 and 7.");
// reading all remainders
Scanner remainder3 = new Scanner(System.in);
Scanner remainder5 = new Scanner(System.in);
Scanner remainder7 = new Scanner(System.in);
int age = ((remainder3 * 70   (remainder5 * 21)   (remainder7 * 15)) % 105);

System.out.println("Your age is "   age   " that's a good time to start programming!");

When I run the program I get this error:

java: bad operand types for binary operator '*'
  first type:  java.util.Scanner
  second type: int

What can I do to debug this program?

I think it's an issue of the age variable not recognizing the variable type "int," so I tried changing that. I also tried adding parentheses but that did not work either.

CodePudding user response：

public static void main(String[] args) {
    
    Scanner keypressReader = new Scanner(System.in);
    System.out.println("Let me guess your age.");
    System.out.println("What is the remainder of dividing your age by 3?");
    int re3 = keypressReader.nextInt();
    System.out.println("What is the remainder of dividing your age by 5?");
    int re5 = keypressReader.nextInt();
    System.out.println("What is the remainder of dividing your age by 7?");
    int re7 = keypressReader.nextInt();
    
    int age = ((re3 * 70   (re5 * 21)   (re7 * 15)) % 105);
    System.out.println("Your age is "   age   " that's a good time to start programming!");
}

Based on what's stated by commenters. this is the basic of how to use Scanner to read integer inputs.

1. Start off by creating a Scanner object.
2. Use System.out.println to have your program interact with the user with a question or a call to action.
3. Use Scanner functions like nextLine, nextDouble, nextInt, etc to get the values from user inputs.
4. Conduct your processing of the inputs by the user.

To get a better grade and impress your teacher, you should look into how to cater for error inputs. e.g. what if the user enter alphabets instead of a numerical value?

CodePudding user response：

You have to use scanner.nextLine() to read input. Currently, you are trying to multiply the Scanner itself with a number, which throws an error.

You can declare one Scanner with new Scanner(System.in) and then read the lines as follows:

int remainder3 = Integer.valueOf(scanner.nextLine());
int remainder5 = Integer.valueOf(scanner.nextLine());
int remainder7 = Integer.valueOf(scanner.nextLine());