练习

一维数组线性查找法

public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    int[] array = {11,23,234,12,3,45,21,233,23,32,123,321};
    System.out.println("请输入您要查找的数：");
    int num = input.nextInt();
    int index = -1;
    for (int i = 0; i < array.length; i++) {
        if(array[i]==num){
            index = i+1;
            break;
        }
    }
    if(index!=-1){
        System.out.println("find 在数组中的第"+index+"个位置");
    }else{
        System.out.println("not find！");
    }
}

一维数组线性查找法（求最大值和最小值）

public static void main(String[] args) {
    int[] array = {11,23,234,12,3,45,21,233,23,32,123,321};
    int max = array[0];
    int min = array[0];
    for (int i = 0; i < array.length; i++) {
        if(array[i]>max){
            max = array[i];
        }
        if(array[i]<min){
            min = array[i];
        }
    }
    System.out.println("最大值："+max);
    System.out.println("最小值："+min);
}

二分查找法（数组的值必须是有序的）

public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    System.out.println("请输入一个数：");
    int num = input.nextInt();
    int[] array = {1,2,3,4,5,6,7,8,9,0};
    int index = -1;
    int start = 0;
    int end = array.length-1;
    int middle;
    while(start<=end){
        //找到中间数的下标
        middle = (start+end)/2;
        if(num==array[middle]){
            index = middle;
            break;
        }
        if(num>array[middle]){
            start = middle+1;
        }
        if(num<array[middle]){
            end = middle-1;
        }
    }
    if(index!=-1){
        System.out.println("find 在数组中的第"+(index+1)+"个位置。");
    }else{
        System.out.println("not find!");
    }
}

冒泡排序法

public static void main(String[] args) {
    int[] array = {11,23,234,12,3,45,21,233,23,32,123,321};
    for (int i = 0; i < array.length; i++) {
        for (int j = 0; j < array.length-1; j++) {
            if(array[j]>array[j+1]){
                int temp = array[j];
                array[j]=array[j+1];
                array[j+1]=temp;
            }
        }
    }
    for (int i = 0; i < array.length; i++) {
        System.out.print(array[i]+"	");
    }
}