publicclassJiaQi{publicstaticvoidmain(String[]args){publicinterfaceInterface{publicabstractvoidArrayStack();publicabstractbooleanisEmpty();publicabstractvoidmakeEmpty();p...
public class JiaQi
{
public static void main(String[] args)
{
public interface Interface
{
public abstract void ArrayStack ();
public abstract boolean isEmpty();
public abstract void makeEmpty();
public abstract void top();
public abstract void pop();
public abstract void topAndPop();
public abstract void push();
public static final int DEFAULT_CAPACITY = 10;
}
//System.out.println("Hello World!");
class text implements Interface
{
private int[] theArray;
private int topOfStack;
public void ArrayStack()
{
theArray = new int[DEFAULT_CAPACITY];
topOfStack = -1;
}
public boolean isEmpty()
{
return topOfStack == -1;
}
public void makeEmpty()
{
topOfStack = -1;
}
public void push(int x)
{
if(topOfStack + 1 == theArray.length)
System.out.println("over flow");
else
theArray[++topOfStack] = x;
}
public int top()
{
if(isEmpty())
System.out.println("the ArrayStack is empty");
else
return theArray[topOfStack];
}
public viod pop()
{
if(isEmpty())
System.out.println("the ArrayStack is empty");
else
topOfStack--;
}
public int topAndPop()
{
if(isEmpty())
System.out.println("the ArrayStack is empty");
else
return theArray[topOfStack--];
}
}
}
}
编译后
JiaQi.java:5: 非法的表达式开始
public interface Interface
^
JiaQi.java:5: 需要 ';'
public interface Interface
^
2 错误
------------------------------------
程序怎么回事呀?
------------------------------------
小弟有点不明白，我在网上查了下，怎么非法表达式开始错误分好多，具体怎么回事，高手能给总结下吗？
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public class Main {
public static void main(String[] args) {
/**
* 这里面不应该有private这种限定符
*/
private int a = 1;
int b = 2;
protected int c = 3;
public int d = 4;
System.out.println(a + " " + b + " " + c + " " + d);
}
}
改写如下public class Main {
private int a = 1;
int b = 2;
protected int c = 3;
public int d = 4;
public static void main(String[] args) {
Main m = new Main();
m.display();
}
private void display() {
System.out.println(a + " " + b + " " + c + " " + d);
}
}
或者public class Main {
private static int a = 1;
static int b = 2;
static protected int c = 3;
static public int d = 4;
public static void main(String[] args) {
System.out.println(a + " " + b + " " + c + " " + d);
}
}

importjava.util.Scanner;publicclassTriangles{publicstaticvoidmain(String[]args){doubleX1,Y1,X2,Y2,X3,Y3,POT;finaldoubleminX=0;finaldoubleminY=0;finaldoublemaxX=40;finaldo...
import java.util.Scanner;
public class Triangles
{
public static void main(String[] args)
{
double X1,Y1,X2,Y2,X3,Y3,POT;
final double minX = 0;
final double minY = 0;
final double maxX = 40;
final double maxY = 40;
Scanner input = new Scanner(System.in);
System.out.print("Tis program calculates the perimeter of a Triangle.");
if (X1 >= minX || X1 <= maxX)
System.out.print("Enter X of point 1:");
else
{
System.out.println("Your X1 value is not accpect for this program, please enter the value between 0 to 40.");
X1 = input.nextDouble();
}
if(Y1 >= minY || Y1 <= maxY)
System.out.print("Enter Y of point 1:");
else
{
System.out.println("Your Y1 value is not accpect for this program, please enter the value between 0 to 40.");
Y1 = input.nextDouble();
}
if(X2 >= minX || X2 <= maxX)
System.out.print("Enter X of point 2:");
else
{
System.out.println("Your X2 value is not accpect for this program, please enter the value between 0 to 40.");
X2 = input.nextDouble();
}
if(Y2 >= minY || Y2 <= maxY)
System.out.print("Enter X of point 2:");
else
{
System.out.println("Your Y2 value is not accpect for this program, please enter the value between 0 to 40.");
Y2 = input.nextDouble();
}
if(X3 >= minX || X3 <= maxX)
System.out.print("Enter X of point 3:");
else
{
System.out.println("Your X3 value is not accpect for this program, please enter the value between 0 to 40.");
X3 = input.nextDouble();
}
if(Y3 >= minY || Y3 <= maxY)
System.out.print("Enter X of point 3:");
else
{
System.out.println("Your Y3 value is not accpect for this program, please enter the value between 0 to 40.");
Y3 = input.nextDouble();
}
POT = (Math.sqrt(Math.pow(X2-X1,2)) + (Math.pow(Y2-Y1,2)))+(Math.sqrt(Math.pow(X3-X1,2)) + (Math.pow(Y3-Y1,2)))+(Math.sqrt(Math.pow(X2-X3,2)) + (Math.pow(Y3-Y2,2)));
System.out.println("The perimeter of Triangle with Point1("+X1+","+Y1+"),point2("+X2+","+Y2+", and point3("+X3+","+Y3+")");
System.out.println("is"+POT+);
}
}
>javac Triangles.java
Triangles.java:80: 错误: 非法的表达式开始
System.out.println("is"+POT+);
^
1 个错误
>Exit code: 1
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importjava.awt.*;publicclassCaluextendsFrame{publicCalu(){setLayout(newBorderLayout());Panelp1=newPanel();p1.add(newTextField("",20));add("North",p1);Panelp2=newPanel();p...
import java.awt.*;
public class Calu extends Frame{
public Calu(){
setLayout(new BorderLayout());
Panel p1=new Panel();
p1.add(new TextField("    ",20));
add("North",p1);
Panel p2=new Panel();
p2.setLayout(new GridLayout(5,3);
p2.add(new Button("1"));
p2.add(new Button("2"));
p2.add(new Button("3"));
p2.add(new Button("4"));
p2.add(new Button("5"));
p2.add(new Button("6"));
p2.add(new Button("7"));
p2.add(new Button("8"));
p2.add(new Button("9"));
p2.add(new Button("0"));
p2.add(new Button("+"));
p2.add(new Button("-"));
p2.add(new Button("*"));
p2.add(new Button("/"));
p2.add(new Button("="));
add("Center",p2);
public static void main(String[]args){
Calu window=new Calu();
window.setTitle("MyCaluator");
window.pack();
window.show();
}
}
}
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