# C Program: Generating Triangular Numbers (Recursive Function)

This C program checks whether a given number by user is Triangular number or not uisng **Recursive Function**. ** Triangular Numbers** are those numbers which are obtained by continued summation of the natural numbers 1, 2, 3, 4, 5, etc.

**Triangular Number Example:** 15 is Triangular Number because it can be obtained by **1+2+3+4+5+6** i.e. **1+2+3+4+5+6=15**

**List of Triangular Numbers:** 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91, 105, 120, 136, 153, 171, 190, 210, 231, 253, 276, 300, 325, 351, 378, 406, 435, 465, 496, 528, 561, 595, 630, 666,

## C Source Code: Check Triangular Number Using Recursion

```
#include<stdio.h>
#include<conio.h>
/* Function prototype */
int triangular(int n);
/* Main Function */
int main()
{
int term, i;
clrscr();
printf("How many terms?\n");
scanf("%d", &term);
printf("First %d triangular numbers are:\n", term);
for(i=1; i<=term; i++)
{
printf("%d\t", triangular(i));
}
getch();
return 0;
}
/* Function definition */
int triangular(int n)
{
if(n<=1)
{
return 1;
}
else
{
return n+triangular(n-1); /* Recursive Function */
}
}
```