C Program to find given number is sum of first n natural numbers

#include <stdio.h>
int findSum(int data)
{
    int sum = 0, i, isEqual = 0;
    // Start adding numbers from 1
    for (i = 1; sum < data; i++)
    {
        sum += i;
        // If sum becomes equal to data
        // return i
        if (sum == data)
        {
            isEqual = i;
        }
    }
    return isEqual;
}
int main()
{
    int data = 15, isSumOfNaturalNumber = 0;
    printf("Enter number = ");
    scanf("%d", &data);
    isSumOfNaturalNumber = findSum(data);
    if(isSumOfNaturalNumber)
    {
        printf ("Sum of Natural number 1 to %d\n",isSumOfNaturalNumber);
    }
    else
    {
        printf("It is not a sum of 1 to n Natural number\n");
    }
    return 0;
}

Output:
Enter number = 10
Sum of Natural number 1 to 4