2022年09月30日Java上机

示例5 -1

JBT5101

public class JBT5101 {
    public static void main(String args[]) {
        /*数组定义方式1*/
        char CHA[];
        CHA = new char[4];
        CHA[0] = 'A';
        CHA[1] = 'B';
        CHA[2] = 'C';
        CHA[3] = 'D';
        show(CHA, "CHA"); //输出数组内容
        /*数组定义方式2*/
        char CHB[] = {'1', '2', '3', '4', '5'};
        show(CHB, "CHB"); //输出数组内容
        /*数组定义方式3*/
        char CHC[] = new char[3];
        CHC[0] = 'a';
        CHC[1] = 'b';
        CHC[2] = 'c';
        show(CHC, "CHC"); //输出数组内容
    }

    static void show(char chs[], String str) {
        for (int i = 0; i < chs.length; i++) {
            System.out.println(str + "[" + i + "]=" + chs[i]);
        }
    }
}

示例5-4

JBT5104

public class JBT5104 {
    public static void main(String[] args) {
        int i, j, Num = 9;
        int b[][] = new int[Num][];
        for (j = 1; j <= Num; j++) {
            b[j - 1] = new int[j];
            for (i = 1; i <= b[j - 1].length; i++)
                b[j - 1][i - 1] = i * j;
        }
        for (j = 1; j <= b.length; j++) {
            for (i = 1; i <= b[j-1].length;
            i++)
            System.out.print(i + "*" + j + "=" + b[j-1][i-1]+" ");
            System.out.println("");
        }
    }
}

示例5-5

JBT5201

public class JBT5201 {
    public static void main(String args[]) {
        int i;
        /*字符串定义方式1*/
        String str1;
        str1 = new String();
        str1 = "This is A method of creating string..";
        System.out.println("str1=" + str1);
        /*字符串定义方式2*/
        String str2;
        str2 = new String("This is B method of creating string..");
        System.out.println("str2=" + str2);
        /*字符串定义方式3*/
        String str3 = new String("This is C method of creating string…");
        System.out.println("str3=" + str3);
        /*字符串组定义方式4*/
        String str4;
        str4 = "This is D method of creating string…";
        System.out.println("str4=" + str4);
        /*字符串定义方式5*/
        String str5 = "This is E method of creating string…";
        System.out.println("str5=" + str5);
    }
}

示例5-7

JBT5203

public class JBT5203 {
    public static void main(String[] args) {
        StringBuffer a = new StringBuffer("A");
        StringBuffer b = new StringBuffer("B");
        operate(a, b);
        System.out.println("a=" + a + " b=" + b);
    }

    static void operate(StringBuffer x, StringBuffer y) {
        x.append(y);
        y = x;
        System.out.println("x=" + x + " y=" + x);
    }
}

示例5-8

JBT5301

public class JBT5301 {
    public static void main(String args[]) {
        MyArray my1 = new MyArray();
        char ch = '*';
        char chset[] = {'a', 'b', 'c', '*'};
        String strarr = new String(chset);
        System.out.println(strarr + "中字符" + ch + "的个数为" + my1.countChar(strarr, ch));
    }
}

class MyArray {
    //统计str中字符ch的个数
    public int countChar(String str, char ch) {
        int i, j = 0;
        for (i = 0; i < str.length(); i++)
            if (str.charAt(i) == ch) j = j + 1;
        return j;
    }
}

扩展题

public class ArrayTest {
    private static final int MAX = 10;
    public static void main(String[] args) {
        int[] array = new int[MAX];
        System.out.print("原始数组：");
        for (int i = 0; i < MAX; i++) {
            array[i] = (int) ((Math.random() * 100) + 1);//生成100以内的随机数
            System.out.print(array[i]);
            if (i != MAX - 1) {
                System.out.print(",");
            }
        }
        System.out.println();
        int max = array[0]; // 把数据中的第1个元素存max
        int min = array[0]; // 把数据中的第1个元素存min
        int sum = array[0];
        for (int i = 1; i < array.length; i++) { // 从第二个元素开始遍历数组
            if (array[i] > max) {  // 假如元素大于max 就把当前值赋值给max
                max = array[i];
            }
            if (array[i] < min) {  // 假如元素小于min 就把当前值赋值给min
                min = array[i];
            }
            sum += array[i];
        }
        System.out.println("数组中的最大值：" + max);
        System.out.println("数组中的最小值：" + min);
        System.out.println("数组元素的和：" + sum);
        System.out.println("数组元素的平均值：" + sum / array.length);
    }
}