在 for 循环中工作正常，但手动操作时，会出现 NullPointerException 错误

Question

在我的for循环程序中，它完美地工作，没有错误，但是当我删除for循环并手动增加它时，因为我只想输入一次并存储在数组中，有一个NullPointerException。对我来说它看起来是一样的，唯一的区别是它不循环，而是手动增加它。我该怎么修理它?

public class Javaapp {
public static void main(String[] args) {

Team competitive = new Team ("Cloud9", 5, 14, 18);
Member [] member = new Member [5];
Scanner input = new Scanner(System.in);
int answer = input.nextInt();

for(int i=0; i<competitive.maxMember; i++){ 
System.out.printf("Name:");
String tmpName = input.next();
System.out.printf("Age:");
int tmpAge = input.nextInt();
member[i] = new Member(tmpName, tmpAge);   
}
for(Member m: member){
if (competitive.checkQualification(m) == true){ 
competitive.addMember(m);
System.out.println("You're officially part of the team");
}
else if (competitive.checkQualification(m) == false)
System.out.println("You did not meet the requirements");
}
}
}

Answer 1

问题在这个循环

for(Member m: member){
if (competitive.checkQualification(m) == true){ // The error points in here where it says NullExceptionerror
competitive.addMember(m);
System.out.println("You're officially part of the team");
}
else if (competitive.checkQualification(m) == false)
System.out.println("You did not meet the requirements");
}

因为你没有完成所有成员的输入，当你尝试迭代这个循环时，它会在第一次工作，因为数组中只有一个成员。但是下一次，由于在i=1处没有成员，它将在传递给checkQualification方法时给出NullPointerException。而不是每次循环，只需将成员[i]传递给该函数，然后在i的增量值之后。