[英]Passing values from one nonstatic method to another from main?
我在使用非靜態方法時遇到了麻煩。 我試圖從一種方法中獲取“ side”變量的值,然后將其插入另一個將計算面積的方法中。 有沒有一種方法可以將方法更改為靜態方法? 以前在這里回答的問題都沒有幫助,我的教科書也沒有幫助。
import java.util.*;
public class CubeVolume
{
int side1;
int side2;
int side3;
public void getSides()
{
Scanner input = new Scanner(System.in);
System.out.println("Enter the length of side1");
side1 = input.nextInt();
System.out.println("Enter the length of side2");
side2 = input.nextInt();
System.out.println("Enter the length of side3");
side3 = input.nextInt();
}
public int getVolume(int side1, int side2, int side3)
{
int volume = side1 * side2 * side3;
return volume;
}
public static void main(String[] args)
{
CubeVolume cube = new CubeVolume();
cube.getSides();
cube.getVolume(side1, side2, side3);
}
}
我認為問題出在我的方法調用cube.getVolume(side1,side2,side3); 因為編譯器告訴我不能從靜態上下文引用非靜態變量。
無需將任何參數傳遞給getVolume()
,只需使用類變量:
import java.util.Scanner;
class CubeVolume {
private int side1;
private int side2;
private int side3;
private void getSides() {
Scanner input = new Scanner(System.in);
System.out.print("Enter the length of side1: ");
side1 = input.nextInt();
System.out.print("Enter the length of side2: ");
side2 = input.nextInt();
System.out.print("Enter the length of side3: ");
side3 = input.nextInt();
input.close();
}
private int getVolume() {
return side1 * side2 * side3;
}
private void printAppTitle() {
System.out.println("Cube Volume Calculator");
System.out.println("======================");
}
public static void main(String[] args) {
CubeVolume cube = new CubeVolume();
cube.printAppTitle();
cube.getSides();
String cubeVolumeString = String.valueOf(cube.getVolume());
System.out.println("The cubes volume is: " + cubeVolumeString);
}
}
用法示例:
Cube Volume Calculator
======================
Enter the length of side1: 3
Enter the length of side2: 4
Enter the length of side3: 5
The cube's volume is: 60
將邊長存儲在double數組, sides
中並處理getSides()
可能的無效輸入的getSides()
:
import java.util.Scanner;
class CubeVolume {
private double[] sides;
CubeVolume() {
sides = new double[3];
}
private void getSides() {
Scanner scanner = new Scanner(System.in);
int currentSide = 0;
while (currentSide < sides.length) {
System.out.printf("Enter the length of side %d: ", currentSide + 1);
double nextSide = 0.0;
input:
while (scanner.hasNext()) {
if (scanner.hasNextDouble()){
nextSide = scanner.nextDouble();
if (nextSide > 0) {
sides[currentSide] = nextSide;
break input;
} else {
System.out.println("ERROR: Input number was too small.");
System.out.printf("Enter the length of side %d: ", currentSide + 1);
}
} else {
System.out.println("ERROR: Invalid input, please input a number.");
System.out.printf("Enter the length of side %d: ", currentSide + 1);
scanner.next();
}
}
currentSide++;
}
scanner.close();
}
private double getVolume() {
return sides[0] * sides[1] * sides[2];
}
private void printAppTitle() {
System.out.println("Cube Volume Calculator");
System.out.println("======================");
}
public static void main(String[] args) {
CubeVolume cube = new CubeVolume();
cube.printAppTitle();
cube.getSides();
String cubeVolumeString = String.format("%.2f", cube.getVolume());
System.out.println("The cube's volume is: " + cubeVolumeString);
}
}
用法示例2:
Cube Volume Calculator
======================
Enter the length of side 1: a
ERROR: Invalid input, please input a number.
Enter the length of side 1: -1.1
ERROR: Input number was too small.
Enter the length of side 1: 3.4
Enter the length of side 2: 4.7
Enter the length of side 3: 5.8
The cube's volume is: 92.68
如果要在main()中使用方法,則這些方法必須是靜態的,因為main()是靜態的。 因此,您的方法應聲明為:
public static void getSides() { .... }
public static int getVolume(int side1, int side2, int side3) { .... }
但是,如果您告訴類的實例從main()方法中的非靜態方法開始,則可以避免所有這些情況:
public static void main(String[] args) {
new CubeVolume().startApp(args);
}
private void startApp(String[] args) {
CubeVolume cube = new CubeVolume();
cube.getSides();
cube.getVolume(side1, side2, side3);
}
現在,您不需要在類中的其他方法是靜態的,因為您不是從靜態main()調用它們的。
您不需要傳遞sides參數來獲取valume函數,因為您的sides變量將可用於獲取valume函數。
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