#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!=1&&j!=1)
?????????? {
?????????????? sum+=arr[i][j];
?????????? }
?????????? else{
????????? ??? ?if(i==1&&j==1)
????????? ??? ?{
????????? ??? ??? ?sum+=arr[1][1];
?? ??? ??? ??? }
?????????? }
?????? }
??? }
??? printf("對角線元素之和是：%d\n",sum);
??? return 0;?? ?
}