4*4矩阵两条对角线之和

#include <stdio.h> main() { int i,j,a[4][4]={{1,2,3,4}, {5,6,7,8}, {1,2,3,4}, {5,6,7,8}}, sum=0; for (i=0;i<4;i++) for (j=i;j<=i;j++) sum+=a[i][j]; for (i=0,j=3;i<4,j>=0;i++,j--) sum+=a[i][j]; printf("%d\n",sum); }