[英]Java Error: illegal start of expression
我基本上是在提炼、完成并尝试从 Java 初学者的参考书中编译测试代码。 目标是创建一个猜谜游戏,其中目标位于 3 个连续的单元格中(我将位置保存在一个数组中)并且用户猜测单元格编号。 逐个细胞破坏目标细胞。
我在这里检查了六篇关于相同错误的帖子,但我无法弄清楚出了什么问题。
这是我的错误:
test.java:5: error: illegal start of expression
public int[] locations={1,2,3};
^
1 error
我的代码是:
public class test{
public static void main(String[] args){
test dot=new test();
public int[] locations={1,2,3};
dot.setLocationCells(locations);
String userGuess="2";
String result = dot.checkYourself(userGuess);
String testResult="failed";
if(result.equals("hit")){
testResult="passed";
}
System.out.println(testResult);
}
public String checkYourself(String stringGuess){
int guess=Integer.parseInt(stringGuess);
String result="miss";
int numOfHits=0;
for(int cell:locations){
if(guess==cell){
result="hit";
numOfHits++;
break;
}
}
if(numOfHits==locations.length){
result="kill";
}
System.out.println(result);
return result;
}
public void setLocationCells( int[] locations){
int[] locns;
locns=locations;
}
}
方法只能声明局部变量。 这就是为什么当您尝试将其声明为公共时编译器会报告错误的原因。
对于局部变量,您不能使用任何类型的访问器(公共的、受保护的或私有的)。
您还应该知道 static 关键字的含义。 在方法checkYourself
中,您使用整数数组locations
。
static 关键字区分可通过对象创建访问的元素。 因此它们不是对象本身的一部分。
public class Test { //Capitalized name for classes are used in Java
private final init[] locations; //key final mean that, is must be assigned before object is constructed and can not be changed later.
public Test(int[] locations) {
this.locations = locations;//To access to class member, when method argument has the same name use `this` key word.
}
public boolean checkYourSelf(int value) { //This method is accessed only from a object.
for(int location : locations) {
if(location == value) {
return true; //When you use key word return insied of loop you exit from it. In this case you exit also from whole method.
}
}
return false; //Method should be simple and perform one task. So you can get more flexibility.
}
public static int[] locations = {1,2,3};//This is static array that is not part of object, but can be used in it.
public static void main(String[] args) { //This is declaration of public method that is not part of create object. It can be accessed from every place.
Test test = new Test(Test.locations); //We declare variable test, and create new instance (object) of class Test.
String result;
if(test.checkYourSelf(2)) {//We moved outside the string
result = "Hurray";
} else {
result = "Try again"
}
System.out.println(result); //We have only one place where write is done. Easy to change in future.
}
}
从int[] locations={1,2,3};
中删除public
关键字; . 方法内部不允许使用访问修饰符,因为它的可访问性由其方法范围定义。
如果您的目标是在许多方法中使用此引用,您可能希望将声明移到方法之外。
宣布
public static int[] locations={1,2,3};
在主要方法之外。
public static int [] locations={1,2,3};
public static test dot=new test();
在 main 方法上方声明上述变量,代码编译正常。
public static void main(String[] args){
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