View Compilation Error

0_0_13904446_3376.cpp: In function 'void add(int)':
0_0_13904446_3376.cpp:14:8: error: 'j' was not declared in this scope
   a[n][j++]=k%10000;
        ^
0_0_13904446_3376.cpp: In function 'int main()':
0_0_13904446_3376.cpp:31:7: error: 'i' was not declared in this scope
   for(i=100;i>0;i--)
       ^
0_0_13904446_3376.cpp:34:20: error: 'i' was not declared in this scope
   printf("%d",a[n][i]);
                    ^