练习题5



练习5:

求一个n阶方阵对角线的和

import java.util.*;
public class Matrix {
public static void main(String[] args) {
System.out.println("请输入阶数：n");
Scanner input=new Scanner(System.in);
int n=input.nextInt();
int num[][]=new int [n][n];
System.out.println("请输入"+n+"阶方阵");
int sum1=0,sum2=0;//存两条对角线的和
for(int i=0;i<n;i++){
for(int j=0;j<n;j++){
num[i][j]=input.nextInt();
if(i==j) 
sum1=sum1+num[i][j];
if(i+j==n-1)
sum2=sum2+num[i][j];
}
}    
System.out.print("主对角线"+sum1);        
System.out.print("副对角线"+sum2);
}
}