How to find the elements and 4*4 of each backslash in N-order matrix

#include <stdio.h> void Main () {//00-11-22-33 the first slash is the second 10-21-32 int arr2[4][4] =    
                      {00, 01, 02, 03, 10, 11, 12, 13, 20, 21, 22, 23,    
    30, 31, 32, 33,};    
    int I, J;    
    int sum = 0;    
    int index = 0; for (int i = 0; i < 4; i++) {for (int j = 0; J < 4; J +) {//printf    
            ("Initial i=%d", I);    
            Meet this condition//More Highlights: http://www.bianceng.cnhttp://www.bianceng.cn/Programming/sjjg/if (j-i = j)    
                {int index = j;    
                printf ("\n\n\n%d\n\n", index);    
                printf ("i=%d,j=%d\n", I, j);    
                    for (int i = 0; i < 4; i++) {for (int j = 0; J < 4; J +)    
             {if (j-i = = index)           {sum = Arr2[i][j];    
                } printf ("%d\n Data when y row", sum);    
                System ("pause");    
            sum = 0;    
                } if (i-j = = i) {int index = i;    
                printf ("\n\n\n%d\n\n", index);    
                printf ("i=%d,j=%d\n", i,j);    
                    for (int i = 0; i < 4; i++) {for (int j = 0; J < 4; J +)    
                            {if (i-j = = index) {    
                        Sum + + arr2[i][j];    
                } printf ("%d\n", sum);    
                System ("pause");    
            sum = 0; }} System ("Pause "); }