SEE /...  we cant return 1000 variables at a time ... using
call by value......  only call by reference can do it....
tat is. usage of pointers...... since it will change
directly in the address itself.... that's a specality...


#include<stdio.h>
#include<conio.h>
void fun(int *,int *,int *.............1000 int's );
void main()
{
int a1,b1,c1,d1,.............a1000;
fun(&a1,&a2,...... &a1000);
for(int i=0;i<1000;i++)
printf("\n %d",a1);
getch();
}
void fun(int *a1,int *b2,.......... 1000 ptr declarations)
{
*a1=1;
*a2=2
.
.
.
.
.
.
100th varaible =1000;
}

extending the previous answer by passing array instead of
all variables

you r right sir.... but he has asked 1000 VARIABLES.. so
only i done in this way.....

the first answer is quite long......

just pass an array(1000 elements) and return that.....

#include<stdio.h>
int fun(int *a)
{
    return ++(*a);
}
     
int main()
{
    int a=0,i,d;
      for(i=0;i<100;i++)
      {
                       d=fun(&a);
                       printf("\n%d",d);
      }
    getch();
}