只写了几题(待以后更新.......)
*8.1(求矩阵中各列数字的和)
import java.util.Scanner;
public class E1 {
public static void main(String[] args) {
Scanner input=new Scanner(System.in);
System.out.println("Enter a 3-by-4 matrix row by row: ");
double[][] m=new double[3][4];
for(int row=0; row<m.length; row++) {
for(int column=0; column<m[row].length; column++) {
m[row][column]=input.nextDouble();
}
}
input.close();
for(int column=0; column<4; column++) {
System.out.println("Sum of the elements at column "+column+" is "
+sumColumn( m, column));
}
}
public static double sumColumn(double[][] m, int columnIndex) {
double sum=0;
for(int row=0; row<m.length; row++) {
sum += m[row][columnIndex];
}
return sum;
}
}
*8.2(求矩阵主对角线元素的和)
import java.util.Scanner;
public class E2 {
public static void main(String[] args) {
Scanner input=new Scanner(System.in);
System.out.println("Enter a 4-by-4 matrix row by row: ");
double[][] m=new double[4][4];
for(int row=0; row<m.length; row++) {
for(int column=0; column<m[row].length; column++) {
m[row][column]=input.nextDouble();
}
}
input.close();
System.out.println("Sum of the elements in the major diagonal is "
+sumMajorDiagonal(m));
}
public static double sumMajorDiagonal(double[][] m) {
double sum=0;
for(int row=0; row<m.length; row++) {
sum += m[row][row];
}
return sum;
}
}
*8.3(按考分对学生排序)
略,目前不会
**8.4(计算每个雇员每周工作的时间)
略,看见排序的我要缓一缓
8.5(代数方面:两个矩阵相加)
import java.util.Scanner;
public class E5 {
public static void main(String[] args) {
Scanner input=new Scanner(System.in);
System.out.print("Enter matrix1: ");
double[][] m1=new double[3][3];
for(int row=0; row<m1.length; row++) {
for(int column=0; column<m1[row].length; column++) {
m1[row][column]=input.nextDouble();
}
}
System.out.print("Enter matrix2: ");
double[][] m2=new double[3][3];
for(int row=0; row<m2.length; row++) {
for(int column=0; column<m2[row].length; column++) {
m2[row][column]=input.nextDouble();
}
}
dou