如何使用扫描仪从同一行读取多个浮点数？

Question

I'm a new programmer, and for an assignment I have to write a program that asks the user to enter three numbers, and returns the smallest to them. I don't know how to make each entry it's own float. So far, I have:

static float smallest(float a, float b, float c);

System.out.println("Enter three numbers");

I don't know how to clarify that the next line holds the floats for a, b, and c. We also just learned what "static float smallest" means, and I'm still very confused, so I'm sorry if the answer is obvious.

Answer 1

import java.util.Scanner;

class MyClass {
  public static void main(String[] args) {
    Scanner myObj = new Scanner(System.in);

    System.out.println("Enter three numbers");

    float a = myObj.nextFloat();
    float b = myObj.nextFloat();
    float c = myObj.nextFloat();

    System.out.println("Smallest numb: " + smallest(a, b, c));

  }
}

Answer 2

Change println to print

System.out.print("Enter three numbers: ");

and

use useDelimiter(pattern) in java.util.Scanner

Scanner myObj = new Scanner(System.in).useDelimiter("\\s* \\s*");

Answer 3

From the javadoc for class Scanner :

A Scanner breaks its input into tokens using a delimiter pattern, which by default matches whitespace.

This means you can enter three float numbers separated by a space on one line and read all three with a Scanner .

Apparently you want your program to accept these three numbers from the user. Hence you can create a Scanner that wraps the standard input, ie System.in . Example code follows:

float a;
float b;
float c;
Scanner stdin = new Scanner(System.in);
System.out.print("Enter three numbers: ");
if (stdin.hasNextFloat()) {
    a = stdin.nextFloat();
}
if (stdin.hasNextFloat()) {
    b = stdin.nextFloat();
}
if (stdin.hasNextFloat()) {
    c = stdin.nextFloat();
}

Note that the above code only accepts three float numbers but does not determine which of them is the smallest - since you only asked how to accept three float numbers.

Here is an example of running the above code:

Enter three numbers: 1.1 2.2 3.55