C# program to print all the natural numbers from 1 to N can be written in both iterative and recursive methods. In the iterative method, the task can be performed by using for loop, while loop and do-while loop. Here, all the C# programs using different loops have been covered to print the natural numbers from 1 to N (1, 2, 3, ..., N).

#### Page content(s):

1. Program & Output

1. Algorithm

2. Pseudocode

3. Time Complexity

4. Flowchart

## 1. C# Program & output to Print First N Natural Numbers

Code has been copied
/***********************************
alphabetacoder.com
C# program to print all natual
numbers from 1 to n  using for loop
*************************************/

using System;

namespace PrintNaturalNumber {
class Program {
static void Main(string[] args) {
// declare variables
int n, i;

//take input of the number upto which
// natural numbers will be printed
Console.Write("Enter the upper limit= ");

// iterate from 1 to n and print the number
Console.Write("First " + n + " natural numbers are : ");
for (i = 1; i <= n; i++)
Console.Write(i + " ");

// wait for user to press any key
}
}
}


Output

#### Case 1:

Enter the upper limit=10

First 10 natural numbers are : 1 2 3 4 5 6 7 8 9 10

#### Case 2:

Enter the upper limit=5

First 5 natural numbers are : 1 2 3 4 5

/************************************
alphabetacoder.com
C# program to print all natual
numbers from 1 to n  using while loop
**************************************/

using System;

namespace PrintNaturalNumber {
class Program {
static void Main(string[] args) {
// declare variables
int n, i;

//take input of the number upto which
// natural numbers will be printed
Console.Write("Enter the upper limit= ");

// iterate from 1 to n and print the number
Console.Write("First " + n + " natural numbers are : ");
i = 1;
while (i <= n) {
Console.Write(i + " ");
i = i + 1;
}

// wait for user to press any key
}
}
}


Output

#### Case 1:

Enter the upper limit=10

First 10 natural numbers are : 1 2 3 4 5 6 7 8 9 10

#### Case 2:

Enter the upper limit=5

First 5 natural numbers are : 1 2 3 4 5

/**************************************
alphabetacoder.com
C# program to print all natual numbers
from 1 to n  using do - while loop
***************************************/

using System;

namespace PrintNaturalNumber {
class Program {
static void Main(string[] args) {
// declare variables
int n, i;

//take input of the number upto which
// natural numbers will be printed
Console.Write("Enter the upper limit= ");

// iterate from 1 to n and print the number
Console.Write("First " + n + " natural numbers are : ");
i = 1;
do {
Console.Write(i + " ");
i = i + 1;
} while (i <= n);

// wait for user to press any key
}
}
}


Output

#### Case 1:

Enter the upper limit=10

First 10 natural numbers are : 1 2 3 4 5 6 7 8 9 10

#### Case 2:

Enter the upper limit=5

First 5 natural numbers are : 1 2 3 4 5