Question

编译问题。编译器说即使我在第25行使用它也不使用变量。

错误： [行：21] 警告：未使用本地变量pay的值

// CreatePayroll.java takes wages and hours from file and creates pay file.
import java.util.*;
import java.io.*;
public class CreatePayroll {
  public static void main(String[] args) {
    try{
//Scanner for input file
      File inputFile = new File("employees.txt");
      Scanner fin = new Scanner(inputFile);
//Printwriter for output file
      File outputFile= new File("payroll.txt");
      PrintWriter fout = new PrintWriter(outputFile);
//read input file creates new file
      while ( fin.hasNextLine() ) {
        String firstName = fin.next();
        String lastName = fin.next();
        double wage = fin.nextDouble();
        double hours = fin.nextDouble();
        //Calculates pay
        if (hours > 40) {
          double pay = (wage*40)+((hours-40)*(wage*1.5));
        } else {
          double pay = wage*hours;
//last line to print to out file
          fout.println(firstName + " " + lastName + " $" + pay);
        }
      }
//cleanup
      fin.close();
      fout.close();
      System.out.print("DONE! See 'payroll.txt'.");
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

Answer 1

您有严重的范围问题：您在if和else语句中声明了薪酬变量两次，这意味着这些非常局部的变量只是在这些街区内可见。不要那样做。在if / else块之上声明pay，以便在整个方法中使用它。

所以改变：

if (hours > 40) {
    double pay = (wage*40)+((hours-40)*(wage*1.5));
} else {
    double pay = wage*hours;
    //last line to print to out file
    fout.println(firstName + " " + lastName + " $" + pay);
}

为：

// declare pay prior to the if/else blocks
double pay = 0.0;
if (hours > 40) {
     pay = (wage*40)+((hours-40)*(wage*1.5));
} else {
     pay = wage*hours;
}

// get the line below **out** of the else block
fout.println(firstName + " " + lastName + " $" + pay);

在java中遇到变量问题

1 个答案: