Let us see the numbers program with user define function and structures.

#include<iostream>
using namespace std;
struct counting
{
	int i;
	int j;
	int k=0;

};
void displaydata(counting);
int main(){
	counting c;
	displaydata(c);
	return 0;
}
  void displaydata(counting c){
  	
	for(c.i=0;c.i<=10;c.i++){
		for(c.j=1;c.j<c.i;c.j++){
  	printf("%d",c.k);
  	c.k++;
  }
  	printf("\n");
  }

  }

Output