public class matrix {

    /**
     * @param args
     */
   
    public static int max(int table[])
    {
        int m=table[0];
        for(int i=1;i<table.length;i++)
        {
            if(table[i]>m)
                m=table[i];
        }
        return m;
    }
   
    public static int min(int table[])
    {
        int n=table[0];
        for(int i=0;i<table.length;i++)
        {
            if(table[i]<n)
                n=table[i];
        }
        return n;
    }
   
    public static int indexOf(int table[],int key)
    {
        int index=-1;
        for(int i=0;i<table.length;i++)
        {
            if(key==table[i])
            {
                index=i+1;
                break;
            }
        }
        return index;
    }
   
    public static void sort(int table[])
    {
        for(int i=table.length-1,number=0;i>=1;i--)
            for(int j=0;j<i;j++)
            {
                if(table[j]>table[j+1])
                {
                    number=table[j+1];
                    table[j+1]=table[j];
                    table[j]=number;
                }
            }
    }
   
    public static boolean isSorted(int table[])
    {
        for(int i=table.length-1;i>=0;i--)
        {
            if(table[i]<table[i-1])
                return false;
        }
        return true;
    }
   
    public static void print(int table[])
    {
        for(int i=0;i<table.length;i++)
            System.out.print(table[i]+"\t");
        System.out.println();
    }
   
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int matrix[]={9,5,13,18,19,5,3,2,7,9,6,24,21};
        System.out.println("the max number is: "+max(matrix));
        System.out.println("the min number is: "+min(matrix));
        if(indexOf(matrix,5)==-1)
            System.out.println("the number is not in the matrix!");
        else
        {
            System.out.println("the index of the number is: "+indexOf(matrix,5));
        }
        System.out.print("the number in matrix are:");        print(matrix);
        sort(matrix);
        System.out.println("the matrix is sorted?"+"\t"+(isSorted(matrix)?"YES":"NO"));
        System.out.print("the number in matrix are:");        print(matrix);
    }

}
已解决 不要去运行程序 看你眼力如何了 能找出问题不

说实话，真没耐心看，希望LZ下次把代码格式化一下放在之间。另：为什么要重写排序方法呢，Java自带的Arrays.sort(matrix);不能满足你的需要吗？重写的方法效率不见得高吧。

public static boolean isSorted(int table[])
    {
        for(int i=table.length-1;i>=0;i--)
        {
            if(table[i]<table[i-1])
                return false;
        }
        return true;
    }

table[i-1]当i等于0的时候，table[-1]