JAVA课堂数组

import java.util.Scanner;
public class Text {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner in=new Scanner(System.in);
        System.out.println("输入一个数：");
        double a;
        a=in.nextDouble();
        System.out.println(digitUppercase(a));
    }
    public static String digitUppercase(double n) { 
        String fraction[] = { "角", "分"}; 
        String digit[] = { "零", "壹", "贰", "叁", "肆", "伍", "陆", "柒", "捌", "玖"}; 
        String unit[][] = { { "元", "万", "亿"}, { "", "拾", "佰", "仟"}}; 
        String head = n < 0 ? "负" : ""; 
        n = Math.abs(n); 
        String s = ""; 
        for (int i = 0; i < fraction.length; i++) 
        { 
            s += (digit[(int) (Math.floor(n * 10 * Math.pow(10, i)) % 10)] + fraction[i]).replaceAll("(零.)+", ""); 
        } 
        if (s.length() < 1) 
        { 
            s = "整"; 
        } 
        int integerPart = (int) Math.floor(n); 
        for (int i = 0; i < unit[0].length && integerPart > 0; i++)
        { 
            String p = ""; 
            for (int j = 0; j < unit[1].length && n > 0; j++) 
            { 
                p = digit[integerPart % 10] + unit[1][j] + p; 
                integerPart = integerPart / 10; 
            } 
            s = p.replaceAll("(零.)*零$", "").replaceAll("^$", "零") + unit[0][i] + s; 
        } 
        return head + s.replaceAll("(零.)*零元", "元").replaceFirst("(零.)+", "").replaceAll("(零.)+", "零").replaceAll("^整$", "零元整"); 
    } 
}

import java.util.Scanner;
public class Text {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String s1,s2;
        Scanner in=new Scanner(System.in);
        System.out.println("输入第一个大数：");
        s1=in.next();
        System.out.println("输入第二个大数：");
        s2=in.next();
        System.out.println(add(s1,s2));
        System.out.println(sub(s1,s2));
        in.close();
    }
    private static String add(String a, String b) 
    { 
        System.out.print("加法:" + a+ "+" + b + "=");
        char[] aa = new StringBuffer(a).reverse().toString().toCharArray(); 
        char[] bb = new StringBuffer(b).reverse().toString().toCharArray(); 
        int aLen = aa.length; 
        int bLen = bb.length; 
        int len = aLen > bLen ? aLen : bLen; 
        int[] result = new int[len + 1]; 
        for (int i = 0; i < len + 1; ++i) 
        { 
            int aint = i < aLen ? aa[i] - ‘0‘ : 0; 
            int bint = i < bLen ? bb[i] - ‘0‘ : 0; 
            result[i] = aint + bint; 
        } 
        for(int i=0;i<result.length-1;++i)
        { 
            if(result[i]>=10)
            { 
                result[i+1] += result[i]/10; 
                result[i] %= 10; 
            } 
        } 
        boolean flag = true; 
        StringBuffer sb = new StringBuffer(len); 
        for(int i=len;i>=0;--i)
        { 
            if(result[i]==0&&flag)
            { 
                continue; 
            }
            else
            { 
                flag=false; 
            } 
            sb.append(result[i]); 
        } 
        return sb.toString(); 
    } 
    public static String sub(String f, String s) { 
        System.out.print("减法:" + f + "-" + s + "="); 
        char[] a = new StringBuffer(f).reverse().toString().toCharArray(); 
        char[] b = new StringBuffer(s).reverse().toString().toCharArray(); 
        int lenA = a.length; 
        int lenB = b.length; 
        int len = lenA > lenB ? lenA : lenB; 
        int[] result = new int[len]; 
        char sign = ‘+‘; 
        if (lenA < lenB) 
        { 
            sign = ‘-‘; 
        } 
        else if (lenA == lenB) 
        { 
            int i = lenA - 1; 
            while (i > 0 && a[i] == b[i]) 
            { 
                i--; 
            } 
            if (a[i] < b[i]) 
            { 
                sign = ‘-‘; 
            } 
        } 
        // 计算结果集，如果最终结果为正，那么就a-b否则的话就b-a 
        for (int i = 0; i < len; i++) 
        { 
            int aint = i < lenA ? (a[i] - ‘0‘) : 0; 
            int bint = i < lenB ? (b[i] - ‘0‘) : 0; 
            if (sign == ‘+‘) 
            { 
                result[i] = aint - bint; 
            } 
            else
            { 
                result[i] = bint - aint; 
            } 
        } 
        // 如果结果集合中的某一位小于零，那么就向前一位借一，然后将本位加上10。其实就相当于借位做减法 
        for (int i = 0; i < result.length - 1; i++) 
        { 
            if (result[i] < 0)
            { 
                result[i + 1] -= 1; 
                result[i] += 10; 
            } 
        } 
        StringBuffer sb = new StringBuffer(); 
        // 如果最终结果为负值，就将负号放在最前面，正号则不需要 
        if (sign == ‘-‘) 
        { 
            sb.append(‘-‘); 
        } 
        // 判断是否有前置0 
        boolean flag = true; 
        for (int i = len - 1; i >= 0; i--) 
        { 
            if (result[i] == 0 && flag) 
            { 
                continue; 
            } 
            else
            { 
                flag = false; 
            } 
            sb.append(result[i]); 
        } 
        // 如果最终结果集合中没有值，就说明是两值相等，最终返回0 
        if (sb.toString().equals("")) 
        { 
            sb.append("0"); 
        } 
        // 返回值 
        System.out.println(sb.toString()); 
        return sb.toString(); 
    } 
}

import javax.swing.JOptionPane;
public class Text {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int a[],sum=0;
        a=new int[10];
        String output=new String();
        for(int i=0;i<a.length;i++)
        {
            a[i]=(int)(Math.random()*100);
        }
        output+="a[10]={";
        for(int i=0;i<a.length;i++)
        {
            output+=a[i]+" ";
        }
        output+="}";
        for(int i=0;i<a.length;i++)
        {
            sum+=a[i];
        }
        output+="\nsum:"+sum;
        JOptionPane.showMessageDialog(null, output,"结果",
                JOptionPane.PLAIN_MESSAGE);
    }
}