#include <stdio.h>
int main()
{
??? int arr[3][3] = {{1,2,3},{4,5,6},{7,8,9}};
??? int i,j;
??? int sum=0;
??? for(i=0;i<3;i++)
??? {
?????? for(j=0;j<3;j++)
?????
???????? if(i==0||i==2&&j==0||j==2)
?????? {
?????????? sum=sum+arr[i][j];
?????? }
????? else(i==1&&j==1)
????? {
????????? sum=sum+arr[i][j];
????? }
??? }
??? printf("對(duì)角線元素之和是：%d\n",sum);
??? return 0;???
}