public int getSum(int[][] arr) { //判断矩阵格式是否正确 if (arr == null || arr[0] == 0 || arr.length != arr[0].length) return 0; int len = arr.length; int sum = 0; for (int i = 0; i < len; i++) { sum += arr[i][i]; //主对角线 sum += arr[i][len-i]; //次对角线 } return sum; } 楼主给分吧 :)
public class Test1{ public static void test(String str){ if(str==null|str.length()==0){//非短路格式,两个都要算 System.out.println("String is empty"); }else{ System.out.println("String is not empty"); } } public static void main(String[] args) { int i, j, sum = 0; int count = 1; int a[][] = new int[3][3]; for (i = 0; i < 3; i++) { for (j = 0; j < 3; j++) { a[i][j] =count; //1 初始化数组 count++; } } //打印二维数组 for (i = 0; i < 3; i++) { for (j = 0; j < 3; j++) { System.out.print(a[i][j]+ " "); //2 } System.out.println(" "); } //显示对角线之和 for (i = 0; i < 3; i++) { sum =sum+a[i][i]; //3 } System.out.println("对角线之和:" + sum); test(null);
public int getSum(int[][] arr) {
//判断矩阵格式是否正确
if (arr == null || arr[0] == 0 || arr.length != arr[0].length)
return 0;
int len = arr.length;
int sum = 0;
for (int i = 0; i < len; i++) {
sum += arr[i][i]; //主对角线
sum += arr[i][len-i]; //次对角线
}
return sum;
}
楼主给分吧 :)
public static void test(String str){
if(str==null|str.length()==0){//非短路格式,两个都要算
System.out.println("String is empty");
}else{
System.out.println("String is not empty");
}
}
public static void main(String[] args) {
int i, j, sum = 0;
int count = 1;
int a[][] = new int[3][3];
for (i = 0; i < 3; i++) {
for (j = 0; j < 3; j++) {
a[i][j] =count; //1 初始化数组
count++;
}
}
//打印二维数组
for (i = 0; i < 3; i++) {
for (j = 0; j < 3; j++) {
System.out.print(a[i][j]+ " "); //2
}
System.out.println(" ");
}
//显示对角线之和
for (i = 0; i < 3; i++) {
sum =sum+a[i][i]; //3
}
System.out.println("对角线之和:" + sum);
test(null);