Java 在String.split()和null值之后进行分析
我正在尝试在拆分为int后解析字符串。打印此字符串时,我收到空值Java 在String.split()和null值之后进行分析,java,Java,我正在尝试在拆分为int后解析字符串。打印此字符串时,我收到空值 public class Usage { public int[] vectorA, vectorB; public String value; public String[] valueSplittedA, valueSplittedB; public void scan(){ Scanner sc = new Scanner(System.in); value = s
public class Usage {
public int[] vectorA, vectorB; public String value;
public String[] valueSplittedA, valueSplittedB;
public void scan(){
Scanner sc = new Scanner(System.in);
value = sc.nextLine();
}
public void scanLine(){ //Get users values for vectors
System.out.println("Enter the first Vector\n");
scan();
valueSplittedA = value.split(" ");
System.out.println("Enter the second Vector\n");
scan();
valueSplittedB = value.split(" ");
for(int i = 0; i<valueSplittedA.length; i++){
String temp = valueSplittedA[i];
vectorA[i] = Integer.parseInt(temp);
}
for(int i = 0; i<valueSplittedB.length; i++){
String temp = valueSplittedB[i];
vectorB[i] = Integer.parseInt(temp);
}
System.out.println(vectorA);
System.out.println(vectorB);
}
}
矢量的两个打印都显示为空。怎么了?您忘记初始化向量变量了
public int[] vectorA, vectorB; <-- declared but not initialized
vectorA=newint[valueSplittedA.length];
对于(inti=0;i您忘记初始化数组。这是完整的工作程序
import java.util.Scanner;
import cern.colt.Arrays;
public class Usage {
public int[] vectorA, vectorB; public String value;
public String[] valueSplittedA, valueSplittedB;
public void scan(){
Scanner sc = new Scanner(System.in);
value = sc.nextLine();
}
public void scanLine(){ //Get users values for vectors
System.out.println("Enter the first Vector\n");
scan();
valueSplittedA = value.split(" ");
vectorA = new int[valueSplittedA.length];
System.out.println("Enter the second Vector\n");
scan();
valueSplittedB = value.split(" ");
vectorB = new int[valueSplittedB.length];
for(int i = 0; i<valueSplittedA.length; i++){
String temp = valueSplittedA[i];
vectorA[i] = Integer.parseInt(temp);
}
for(int i = 0; i<valueSplittedB.length; i++){
String temp = valueSplittedB[i];
vectorB[i] = Integer.parseInt(temp);
}
System.out.println(Arrays.toString(vectorA));
System.out.println(Arrays.toString(vectorB));
}
public static void main(String[] args){
Usage u = new Usage();
u.scanLine();
}
import java.util.Scanner;
导入cern.colt.array;
公共类用法{
公共int[]向量a,向量b;公共字符串值;
公共字符串[]valueSplittedA,valueSplittedB;
公共无效扫描(){
扫描仪sc=新的扫描仪(System.in);
值=sc.nextLine();
}
public void scanLine(){//获取向量的用户值
System.out.println(“输入第一个向量\n”);
扫描();
valueSplittedA=value.split(“”);
vectorA=新整数[valueSplittedA.length];
System.out.println(“输入第二个向量\n”);
扫描();
valueSplittedB=value.split(“”);
vectorB=新整数[valueSplittedB.length];
对于(inti=0;iI),我没有看到任何代码实际实例化这些数组,尽管我在顶部看到了声明。
System.out.println(Arrays.toString(vectorA));
System.out.println(Arrays.toString(vectorB));
vectorA = new int[valueSplittedA.length];
for(int i = 0; i<valueSplittedA.length; i++){
String temp = valueSplittedA[i];
vectorA[i] = Integer.parseInt(temp);
}
import java.util.Scanner;
import cern.colt.Arrays;
public class Usage {
public int[] vectorA, vectorB; public String value;
public String[] valueSplittedA, valueSplittedB;
public void scan(){
Scanner sc = new Scanner(System.in);
value = sc.nextLine();
}
public void scanLine(){ //Get users values for vectors
System.out.println("Enter the first Vector\n");
scan();
valueSplittedA = value.split(" ");
vectorA = new int[valueSplittedA.length];
System.out.println("Enter the second Vector\n");
scan();
valueSplittedB = value.split(" ");
vectorB = new int[valueSplittedB.length];
for(int i = 0; i<valueSplittedA.length; i++){
String temp = valueSplittedA[i];
vectorA[i] = Integer.parseInt(temp);
}
for(int i = 0; i<valueSplittedB.length; i++){
String temp = valueSplittedB[i];
vectorB[i] = Integer.parseInt(temp);
}
System.out.println(Arrays.toString(vectorA));
System.out.println(Arrays.toString(vectorB));
}
public static void main(String[] args){
Usage u = new Usage();
u.scanLine();
}