 # R Program to find sum of natural numbers

August 2, 2021, Learn eTutorial
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## How to find the sum of natural numbers?

Natural numbers are the whole numbers that occur naturally from 1 to n. these are also called cardinal numbers because they are used for counting. we can calculate the sum of natural numbers by

n*(n+1)/2

## How sum of natural numbers is implemented in R Program?

We are using `readline()` function for taking the user's input. In this R program, we accept the user's values into n by providing an appropriate message to the user using '`prompt`'. We can use a` while loop` to iterate until the number becomes zero. In each iteration, add the number n to the sum. This total sum is given as output.

## ALGORITHM

STEP 1: prompting appropriate messages to the user

STEP 2: take user input using `readline()` into variables n

STEP 3: use while loop to iterate until the n becomes zero.

STEP 4: in each iteration, we add the number n to sum as sum = sum + n

STEP 5: set n = n - 1

STEP 6: print the sum as output

## R Source Code

```                                          ```n = as.integer(readline(prompt = "Enter a number: "))
if(n< 0) {
print("Enter a positive number")
} else {
sum = 0
# use while loop to iterate until zero
while(n > 0) {
sum = sum + num
n = n - 1
}
print(paste("The sum of numbers up to the given limit is", sum))
}```
```

## OUTPUT

```Enter a number: 10
 "The sum of numbers up to the given limit is 55"```