Without Formula:
num = as.integer(readline(prompt = "Enter a number: ")) if(num < 0) { print("Enter a positive number") } else { sum = 0 # use while loop to iterate until zero while(num > 0) { sum = sum + num num = num - 1 } print(paste("The sum is", sum)) }
Output:
Enter a number: 4 [1] "The sum is 10"
With formula:
num = as.integer(readline(prompt = "Enter a number: ")) if(num < 0) { print("Enter a positive number") } else { sum = (num * (num + 1)) / 2; print(paste("The sum is", sum)) }
Output:
Enter a number: 7 [1] "The sum is 28"