JAVA-1.4-homework

/*1.定义长度位5的整型数组,输入他们的值,用冒泡排序后输出.
 */
package study;
import java.util.*;
public class homework {
    public static void main(String[] args) {
        System.out.println("请输入五个数(用空格或者换行分隔开)：");
        Scanner input=new Scanner(System.in);
        int []a=new int[5];
        int t=0;
        for (int i = 0; i < a.length; i++) {
            a[i]=input.nextInt();
        }
        for (int i = 0; i < a.length-1; i++) {
            for (int j = 0; j < a.length-1-i; j++) {
                if(a[j]>a[j+1]) {
                    t=a[j];
                    a[j]=a[j+1];
                    a[j+1]=t;
                }
            }
        }
        for (int i = 0; i < a.length; i++) {
            System.out.print(a[i]+" ");
        }
    }
    
}

/*2.定义数组{34,22,35,67,45,66,12,33},输入一个数a,
 * 查找在数组中是否存在,如果存在,输出下标,不存在输出"not found"
 */
package study;
import java.util.*;
public class homework {
    public static void main(String[] args) {
        System.out.print("请输入一个数（查找它是否存在于数组中）：");
        Scanner input=new Scanner(System.in);
        int []a={34,22,35,67,45,66,12,33};
        int t=input.nextInt();
        int b=-1;
        for (int i = 0; i < a.length; i++) {
            if(t==a[i]) {
                b=i;
            }
        }
        if(b>-1) {
            System.out.println("数组中存在，下标是："+b);
        }else {
            System.out.println("not found");
        }
    }
    
}

/*3.以矩阵的形式输出一个double型二维数组（长度分别为5、4，值自己设定）的值。
 */
//错误提示：二维数组长度为5，4的定义为a[5][4],正确代码在页尾。
package study;
import java.util.*;
public class homework {
    public static void main(String[] args) {      
        double[][] a= {{4.2,5.6,7.0,5.5,12.0},{1.2,6.5,7.9,85.6,4.8},
                {8.88,41.2,12.3,5.3,1.11},{4.5,8.5,7.9,32.4,58.8}};
        for (int i = 0; i < a.length; i++) {
            for (int j = 0; j < 5; j++) {
                System.out.print(a[i][j]+"	");
            }
            System.out.print("
");
        }
    }
    
}

/*4.定义一个二维数组(长度分别为3,4,值自己设定),求该二维数组的最大值.
 */
//错误提示：二维数组长度为3，4的定义为a[3][4],正确代码在页尾。
package study;
import java.util.*;
public class homework {
    public static void main(String[] args) {      
        double[][] a= {{4.2,5.6,7.0},{1.2,6.5,7.9},
                {12.3,5.3,1.11},{7.9,32.4,58.8}};
        double max1=0.0,max2=0.0;
        for (int i = 0; i < a.length; i++) {
            for (int j = 0; j < 3; j++) {
                for (int h = j+1; h < 3; h++) {
                    if(a[i][j]>a[i][h]) {
                        max1=a[i][j];
                    }else {
                        max1=a[i][h];
                    }
                }
            }
            if(max1>max2) {
                max2=max1;
            }
        }
       System.out.println(max2);
    }
    
}
 

/*3.以矩阵的形式输出一个double型二维数组（长度分别为5、4，值自己设定）的值。
 */
//更正：
package study;
import java.util.*;
public class homework {
    public static void main(String[] args) {      
        double[][] a= {{4.2,5.6,7.0,5.5},{1.2,6.5,7.9,85.6},
                {8.88,41.2,12.3,5.3},{4.5,8.5,7.9,32.4},{12.0,4.8,1.11,58.8}};
        for (int i = 0; i < a.length; i++) {
            for (int j = 0; j < 4; j++) {
                System.out.print(a[i][j]+"	");
            }
            System.out.print("
");
        }
    }
    
}

/*4.定义一个二维数组(长度分别为3,4,值自己设定),求该二维数组的最大值.
 */
//更正：
package study;
import java.util.*;
public class homework {
    public static void main(String[] args) {      
        double[][] a= {{4.2,5.6,7.0,3.5},{1.2,6.5,7.9,7.8},
                {12.3,5.3,1.11,99.9}};
        double max1=0.0,max2=0.0;
        for (int i = 0; i < a.length; i++) {
            for (int j = 0; j < 4; j++) {
                for (int h = j+1; h < 4; h++) {
                    if(a[i][j]>a[i][h]) {
                        max1=a[i][j];
                    }else {
                        max1=a[i][h];
                    }
                }
            }
            if(max1>max2) {
                max2=max1;
            }
        }
       System.out.println(max2);
    }
    
}