乘法表赋值
我正在尝试分配用户输入数组大小并添加数字 1-数组大小,然后打印出列和行数组,但我认为我做得不太正确:
import java.util.Scanner;
public class MultTable
{
public static int[]rows;
public static int[]cols;
public static void main (String args[])
{
intro();
getRows();
getCols();
fillRows();
fillCols();
printTable();
}
public static void intro()
{
System.out.print("Welcome to the Multiplication Table program!");
}
public static void getRows()
{
Scanner input=new Scanner (System.in);
System.out.print("\nEnter number of row:");
int sizerow=input.nextInt();
int rows[]=new int[sizerow];
}
public static void getCols()
{
Scanner input=new Scanner(System.in);
System.out.print("Enter number of columns:");
int sizecol=input.nextInt();
int cols[]=new int[sizecol];
}
public static void fillRows()
{
for(int i=1;i<=rows.length;i++)
{
int rows[]=new int[i];
}
}
public static void fillCols()
{
for(int j=0;j<cols.length;j++)
{
int cols[]=new int[j];
}
}
public static void printTable()
{
System.out.print("\n\nHere is your %dx%d multiplication table:");
System.out.print(cols);
System.out.print("--------");
for(int i=1; i<=rows.length;i++)
{
for(int j=1;j<=cols.length;j++)
{
System.out.print(rows[i]*cols[j]);
}
}
}
}
它一直在说:
MultTable.fillRows(MultTable.java:41)的线程“主”java.lang.NullPointerException异常在 MultTable.main(MultTable.java:13)