java编译是出现 需要.class是什么错误

Question

我是手动编译的
public class ArrayEqual {
static boolean areEqual(int[][] x, int[][] y) {
for(int i=0; i<x.length; i++) {
for(int j=0; j<x[i].length; j++) {
if(x[i][j] != y[i][j]) {
return false;
}
}
}
return true;
}
static boolean isEqual(int[][] x, int[][] y) {
if(x.length == y.length) {
for(int i=0; i<x.length; i++) {
if(x[i].length != y[i].length) {
return false;
}
}
return true;
}
return false;
}
public static void main(String[] args) {
int x[][] = {{1,2}, {2,3}, {3,4,}};
int y[][] = {{1,2}, {2,3}, {3,4,}};
boolean judge;
ArrayEqual ae = new ArrayEqual();

judge = ae.isEqual(x[][], y[][]);

if(judge == true) {
judge = ae.areEqual(x[][], y[][]);
}
System.out.println(judge);
}
}
这就是一个二维数组是否相等的小程序
编译时提示
judge = ae.isEqual(x[][]这, y[][]这);
judge = ae.areEqual(x[][]这, y[][]这);
这四个地方需要“.class”

Answer 1

错误原因1.自定义的方法要设成静态的
2.调用的时候直接写x，y即可。
代码如下
public class ArrayEqual {
static boolean areEqual(int[][] x, int[][] y) {
for (int i = 0; i < x.length; i++) {
for (int j = 0; j < x[i].length; j++) {
if (x[i][j] != y[i][j]) {
return false;
}
}
}
return true;
}

static boolean isEqual(int[][] x, int[][] y) {
if (x.length == y.length) {
for (int i = 0; i < x.length; i++) {
if (x[i].length != y[i].length) {
return false;
}
}
return true;
}
return false;
}
public static void main(String[] args) {
int x[][] = { { 1, 2 }, { 2, 3 }, { 3, 4, } };
int y[][] = { { 1, 2 }, { 2, 3 }, { 3, 4, } };
boolean judge;
//ArrayEqual ae = new ArrayEqual();

judge = isEqual(x, y);

if (judge == true) {
judge = areEqual(x, y);
}
System.out.println(judge);
}
}

Answer 2

是手动编译还是用eclipse ？ 看看你的类文件对应的路径对不对？ 如果是软件编译 一般不会错

Answer 3

少jar包吧