How to append elements without overwriting in struct

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C

struct

In this code I'm trying to call

rrandom

to choose one random id and name and put it in buff struct , and second time calling

rrandom

to choose new random value and putting it also in buff struct , how can assign the second value to buff struct without delete the first one?

What I have tried:

#include <stdio.h>    
#include <stdlib.h>   
#include <string.h>  
#define size 4

 typedef struct Org             		
{
   int  id[4]; 
   char name[4][7];  
}org;



struct buff
{
int bid[4];
char bname[4][7];
};
struct buff buf[2];

void rrandom(org select[size]){



int i,j,r=0;
for (i=0; i<1;i++){
       r = (rand() % (4 - 0)) + 0;
   for( j=0;j<4;j++){ 
    buf[i].bid[j]= select[r].id[j] ;
   strcpy(buf[i].bname[j], select[r].name[j]);
   printf("------r=%d \n" ,r);
}}
for ( int i=0; i<2 ;i++){
     
   for(int j=0;j<4;j++){ 
printf("bname %s  bid = %d \n", buf[i].bname[j], buf[i].bid[j]);

}}

}

void main(  )
{
int i,j;
org select[size]; 

sprintf(select[0].name[0],"1ello1");
sprintf(select[0].name[1],"1ello2");
sprintf(select[0].name[2],"1ello3");
sprintf(select[0].name[3],"1ello4");

sprintf(select[1].name[0],"2ello1");
sprintf(select[1].name[1],"2ello2");
sprintf(select[1].name[2],"2ello3");
sprintf(select[1].name[3],"2ello4");

sprintf(select[2].name[0],"3ello1");
sprintf(select[2].name[1],"3ello2");
sprintf(select[2].name[2],"3ello3");
sprintf(select[2].name[3],"3ello4");

sprintf(select[3].name[0],"4ello1");
sprintf(select[3].name[1],"4ello2");
sprintf(select[3].name[2],"4ello3");
sprintf(select[3].name[3],"4ello4");

sprintf(select[4].name[0],"5ello1");
sprintf(select[4].name[1],"5ello2");
sprintf(select[4].name[2],"5ello3");
sprintf(select[4].name[3],"5ello4");


   printf(" Initial id :\n");
   for(i=0;i<4 ;i++)                         
    {
        for(j=0;j< 4;j++)            			
        { 
             select[i].id[j]= j;  		
}}


rrandom(select);
rrandom(select);

for ( int i=0; i<2 ;i++){
     
   for(int j=0;j<4;j++){ 
printf("from main bname %s  bid = %d ", buf[i].bname[j], buf[i].bid[j]);

}
printf("\n\n");
}

}