java - 在 JAVA 公式中使用 If 语句

Question

我正在为我的 JAVA 开发一个研讨会。有一部分我很难理解:根据性别应用以下公式(必须使用 if 语句): Hmale_child = ((Hmother * 13/12) + Hfather)/2 或者 Hfemale_child = ((Hfather * 12/13) + Hmother)/2

如何对这些公式使用 if 语句？如果用户输入他们 child 的性别是男性，我会使用 Hmale_child。但我见过的所有 if 语句都与数字有关。谁能指出我正确的方向？

类似于:if (gender == male) ??

---

import java.util.Scanner;

public class WKSP6Trial
{  
public static void main(String[] args)
{
  Scanner scannerObject = new Scanner(System.in);

  Scanner inp = new Scanner(System.in);
  String Letter; 
  String input = "";
  String exit = "exit";
  boolean isStringLetter = true;
  System.out.println("Welcome! If at any time you wish to exit the program, type the word exit, and press enter.");

  while(true)
  {
      System.out.println("\nPlease enter letters m or f only as you enter your child's gender: ");
      input = inp.nextLine();

      if(input.equalsIgnoreCase(exit)){break;}
      isStringLetter = input.matches("[m/f/M/F]+");
      if(isStringLetter == false)
      {
         System.out.println("\nYou entered a non letter " + input);
         System.out.println("Remove all non letters aside from m or f from your input and try again !");
         break;
      }

  System.out.println("You entered the gender of your child.");

  System.out.println("Next enter the height of the child's father in feet followed by ");
  System.out.println("the father's height in inches: ");

  int n1, n2;
  n1 = scannerObject.nextInt();
  n2 = scannerObject.nextInt();
  System.out.println("You entered " + n1 + " followed by " + n2);

  System.out.println("Finally, enter the height of the child's mother followed by ");
  System.out.println("the mother's height in inches: ");

  int d1, d2;
  d1 = scannerObject.nextInt();
  d2 = scannerObject.nextInt();
  System.out.println("You entered " + d1 + " followed by " + d2);

  Scanner in = new Scanner(System.in);

     System.out.print("Convert from: ");
      String fromUnit = in.nextLine();
      System.out.print("Convert to: ");
      String toUnit = in.nextLine();


      //below is what I'm uncertain of
      if(gender == m)
      Hmale_child = ((Hmother * 13/12) + Hfather)/2;
  }
}
}

Answer 1

您可以使用 equals 或 equalsIgnoreCase检查字符串输入的方法:

if (gender.equalsIgnoreCase("m")) {
    child = ((Hmother * 13.0/12) + Hfather)/2.0;
else { // alternatively - check if the gender is female, just to be sure
     child = ((Hfather * 12.0/13) + Hmother)/2.0;
}

编辑:
如果您绝对不能使用 else block ，则可以将相同的逻辑表示为两个 if 语句，因为性别不能同时是 "m"和“f”:

if (gender.equalsIgnoreCase("m")) {
    child = ((Hmother * 13.0/12) + Hfather)/2.0;
}

if (gender.equalsIgnoreCase("f")) {
     child = ((Hfather * 12.0/13) + Hmother)/2.0;
}