Could Someone Please Explain This to Me

Question

As primitive as possible.
Your math teacher asked you to calculate the sum of the numbers 1 to N, where N is a given number.
The given program takes a number as input.

Task
Write code to output the sum of the numbers from 1 to that number, inclusive.

Input Example⬅️: 10
Output Example➡️: 55

int num = Convert.ToInt32(Console.ReadLine());

//my code
int sum =0;
while(num>0)
{
sum+=num;
num--;
}
Console.WriteLine(sum);

https://sololearn.com/compiler-playground/cnmxh1ABZmiu/?ref=app

Answer 1

What don't you understand?
The solution to the question? - It seems like you've answered it, or got the answer from somewhere.
How the code works? - the code takes an input and stores it as the variable "num". Then, it initialises an int "sum". Then, the code goes through a loop (in this case, a while loop). The loop takes the variable "sum" and adds the variable "num" to it. The loop then decreases the variable "num" by 1. When the variable "num" drops to 0, the loop ends and the code outputs the variable "sum".
Does that help?

Answer 2

Djman ,
a short description how this code with a `while` loop is working:

it starts by reading a line of input from the console, which is directly converted from a string (all user inputs are done as strings) to an integer value. (using Convert.ToInt32() ).
this integer value is stored in the variable `num`.

an additional variable `sum` is created (that will be used as a running total), initialized with 0.

a while loop starts which continues to run as long as `num` is greater than 0. inside the loop, the current value of `num` is added to `sum`, and then `num` is decreased by 1. (without decreasing `num`, the loop will be an infinte loop that runs forever.)

the above mentioned algorithm adds all the numbers from the original input down to 1.

when `num` reaches the value of `0`, the loop will be terminated.

outside the loop the final value of `sum` is printed to the console.

Answer 3

Here's a brief explanation for the code:

1. Initialization: int sum = 0; correctly starts the sum at zero.

2. Loop Condition: while(num > 0) ensures the loop continues as long as there are positive numbers to add.

3. Accumulation: sum += num; correctly adds the current number to the running total.

4. Decrement: num--; correctly moves to the next smaller number in the sequence.

5. Output: Console.WriteLine(sum); correctly prints the final calculated sum.

Hope this helps!

Answer 4

Ausgrindtube, Sorry about the vague post. I'll improve on it.

Answer 5

It's fine. A bit more information certainly helps with giving a better answer.