In this tutorial, we will learn about the C# for loop and its working with the help of some examples.
In computer programming, loops are used to repeat a block of code.
For example, let’s say we want to show a message 100 times. Then instead of writing the print statement 100 times, we can use a loop.
That was just a simple example; we can achieve much more efficiency and sophistication in our programs by making effective use of loops.
In this article, we’ll look at for loop in C#.
C# Basic For Loop Examples For Beginners
Write C# program to find sum of odd numbers between 1 to n
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int i, num, sum = 0; // Reading number Console.Write("Enter any number: "); num = Convert.ToInt32(Console.ReadLine()); for (i = 1; i <= num; i += 2) { //Adding current odd number to sum variable sum += i; } Console.WriteLine("Sum of all odd numbers between 1 to " + num + " = " + sum); Console.ReadLine(); } } |
Write C# program to swap first and last digit of a number.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int num, last, first, temp, count = 0; double swap; // Reading number Console.Write("Enter any number: "); num = Convert.ToInt32(Console.ReadLine()); temp = num; last = temp % 10; count = (int)Math.Log10(temp); while (temp >= 10) { temp /= 10; } first = temp; swap = (last * Math.Pow(10, count) + first) + (num - (first * Math.Pow(10, count) + last)); Console.WriteLine("Last Digit:" + last); Console.WriteLine("First Digit:" + first); Console.WriteLine(num + " is swapped to " + swap); Console.ReadLine(); } } |
Write C# program to find the sum of first and last digit of any number.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int num, sum = 0, firstDigit, lastDigit; // Reading number Console.Write("Enter any number: "); num = Convert.ToInt32(Console.ReadLine()); lastDigit = num % 10; firstDigit = num; while (num >= 10) { num = num / 10; } firstDigit = num; //Finding sum of first and last digit sum = firstDigit + lastDigit; Console.WriteLine("Sum of first and last digit: "+ sum); Console.ReadLine(); } } |
Write C# program to find first and last digit of any number.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int num, last; // Reading number Console.Write("Enter any number: "); num = Convert.ToInt32(Console.ReadLine()); last = num % 10; Console.WriteLine("The last digit of entered number: "+ last); while (num >= 10) { num = num / 10; } Console.WriteLine("The first digit of entered number: "+ num); Console.ReadLine(); } } |
Write C# program to calculate product of digits of a number.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int num, product = 1; // Reading number Console.Write("Enter any number: "); num = Convert.ToInt32(Console.ReadLine()); // Repeat the steps till n becomes 0 while (num != 0) { product = product * (num % 10); // Remove the last digit from n num = num / 10; } Console.WriteLine("Product of digits = "+ product); Console.ReadLine(); } } |
Write C# program to reverse a number.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int num, rev = 0; // Reading number Console.Write("Enter any number: "); num = Convert.ToInt32(Console.ReadLine()); //finding reverse number using while loop while (num > 0) { rev = rev * 10; rev = rev + num % 10; num = num / 10; } Console.Write("Reversed number is = "+ rev); Console.ReadLine(); } } |
Write C# program to calculate power using while & for loop.
Calculating power of a number using while loop
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int basenumber, exponent,power, i; // Reading number Console.Write("Enter any number: "); basenumber = Convert.ToInt32(Console.ReadLine()); Console.Write("Enter any number: "); exponent = Convert.ToInt32(Console.ReadLine()); power = 1; i = 1; //caculatinh power of given number while (i <= exponent) { power = power * basenumber; i++; } Console.Write("Power : "+ power); Console.ReadLine(); } } |
Calculating power of a number using for loop
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int basenumber, exponent, i, power; // Reading number Console.Write("Enter any number: "); basenumber = Convert.ToInt32(Console.ReadLine()); Console.Write("Enter any number: "); exponent = Convert.ToInt32(Console.ReadLine()); power = 1; //caculatinh power of given number for (i = 1; i <= exponent; i++) power = power * basenumber; Console.Write("Power : "+ power); Console.ReadLine(); } } |
Write C# program to find factorial of any number.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int num,i; long fact=1; // Reading number Console.Write("Enter any number to calculate factorial: "); num = Convert.ToInt32(Console.ReadLine()); fact = 1; i = 1; //Run loop from 1 to number entered by user while(i <= num) { fact = fact * i; i++; } Console.Write("Factorial of : "+ num +" is " + fact); Console.ReadLine(); } } |
Write C# program check whether a number is Armstrong number or not.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int num, sum = 0, i, r; // Reading number Console.Write("Please enter a number: "); num = Convert.ToInt32(Console.ReadLine()); //Finding armstrong number or not for (i = num; i > 0; i = i / 10) { r = i % 10; sum = sum + r * r * r; } if (num == sum) { Console.WriteLine(num + " is an armstrong number."); } else { Console.WriteLine(num + " is not an armstrong number."); } Console.ReadLine(); } } |
Write C# program find Armstrong numbers between 1 to n.
What is Armstrong number?
An Armstrong number is an n-digit number that is equal to the sum of the nth powers of its digits.
For Example: 407 = 43 + 03 + 73 = 64 + 0 + 343 = 407
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int lower, higher, i, temp1, temp2, remainder, n = 0; double result = 0; // Reading number Console.Write("Please Enter two numbers: "); lower = Convert.ToInt32(Console.ReadLine()); higher = Convert.ToInt32(Console.ReadLine()); Console.Write("Armstrong numbers between " + lower + " and " + higher + " are: "); for (i = lower + 1; i < higher; ++i) { temp2 = i; temp1 = i; // number of digits calculation while (temp1 != 0) { temp1 /= 10; ++n; } // result contains sum of nth power of its digits while (temp2 != 0) { remainder = temp2 % 10; result += Math.Pow(remainder, n); temp2 /= 10; } // checking if number i is equal to the sum of nth power of its digits if (result == i) { Console.WriteLine(i); } // resetting the values to check Armstrong number for next iteration n = 0; result = 0; } Console.ReadLine(); } } |
Write C# program to calculate compound Interest.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { float amount, rate, intrest, time, ci, a; /*Reading amount, rate of intrest and period in years from user */ Console.Write("Type the amount : "); amount = Convert.ToInt32(Console.ReadLine()); Console.Write("Type the interest rate : "); rate = Convert.ToInt32(Console.ReadLine()); Console.Write("Type the period in years: "); time = Convert.ToInt32(Console.ReadLine()); intrest = 1+(rate/100); // ci=pow(intrest,time); ci = 1; for(a = 1; a <= time; a++) ci = ci * intrest; ci = amount * ci - amount; Console.WriteLine("Your compound interest is : "+ ci); Console.ReadLine(); } } |
Write C# program to check whether a number is Prime number or not using while & for loop.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int num, i, f; /*Reading number */ Console.Write("Enter any number: "); num = Convert.ToInt32(Console.ReadLine()); f = 0; for (i = 2; i <= num / 2; i++) { if (num % i == 0) { f = 1; break; } } if (f == 0) Console.WriteLine(num+ " is a Prime Number"); else Console.WriteLine(num+" is a Not Prime Number"); Console.ReadLine(); } } |
Write C# program to check whether a number is palindrome or not.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int num, i, rev; // Reading a number from user Console.Write("Enter any number: "); num = Convert.ToInt32(Console.ReadLine()); rev = num; for (i = 0; num > 0; num = num / 10) { i = i * 10; i = i + (num % 10); } //Checking if reverse number is equal to original num or not. if (rev == i) Console.WriteLine(rev+" is a Palindrome Number."); else Console.WriteLine(rev + " is not a Palindrome Number."); Console.ReadLine(); } } |
Write C# program to print number in words.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int n, num = 0; // Reading a number from user Console.WriteLine("Enter any number to print in words: "); n = Convert.ToInt32(Console.ReadLine()); while (n != 0) { num = (num * 10) + (n % 10); n /= 10; } //print corresponding digit in words till num becomes 0 while (num != 0) { switch (num % 10) { case 0: Console.Write("zero "); break; case 1: Console.Write("one "); break; case 2: Console.Write("two "); break; case 3: Console.Write("three "); break; case 4: Console.Write("four "); break; case 5: Console.Write("five "); break; case 6: Console.Write("six "); break; case 7: Console.Write("seven "); break; case 8: Console.Write("eight "); break; case 9: Console.Write("nine "); break; } num = num / 10; } Console.ReadLine(); } } |
Write C# program to find HCF of any two numbers.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int i, num1, num2, min, HCF = 1; // Reading 2 numbers from user Console.WriteLine("Enter any number to print in words: "); num1 = Convert.ToInt32(Console.ReadLine()); num2 = Convert.ToInt32(Console.ReadLine()); // Find min number between two numbers min = (num1 < num2) ? num1 : num2; for (i = 1; i <= min; i++) { if (num1 % i == 0 && num2 % i == 0) { HCF = i; } } Console.WriteLine("HCF of " + num1 + " and " + num2 + " is: " + HCF); Console.ReadLine(); } } |
Write C# program to find LCM of any two numbers.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int num1, num2, x, y, lcm = 0; Console.Write("Enter the First Number : "); num1 = int.Parse(Console.ReadLine()); Console.Write("Enter the Second Number : "); num2 = int.Parse(Console.ReadLine()); x = num1; y = num2; while (num1 != num2) { if (num1 > num2) { num1 = num1 - num2; } else { num2 = num2 - num1; } } lcm = (x * y) / num1; Console.Write("Least Common Multiple is : " + lcm); Console.ReadLine(); } } |
Write C# program to print alphabets from a to z.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { char ch; Console.WriteLine("Alphabets from a - z are: "); for (ch = 'a'; ch <= 'z'; ch++) { //Printing all alphabets with tab Console.Write(ch+"\t"); } Console.ReadLine(); } } |
Write C# program to print ASCII values of all characters.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int i; // Printing ASCII values from 0 to 255 for (i = 0; i <= 255; i++) { Console.WriteLine("ASCII value of " + i +" = " + i); } Console.ReadLine(); } } |
Write C# program to print multiplication table of a given number.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int i, num; //Reading number Console.WriteLine("Enter number to print table: "); num = Convert.ToInt32(Console.ReadLine()); for (i = 1; i <= 10; i++) { //Printing table of number entered by user Console.Write("{0} X {1} = {2} \n", num, i, num * i); } Console.ReadLine(); } } |
Write C# program to print all natural numbers in reverse order.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int i, num; //Read a number from user Console.Write("Enter any number: "); num = Convert.ToInt32(Console.ReadLine()); /*Running loop from the number entered by user, and Decrementing by 1*/ for (i = num; i >= 1; i--) { Console.WriteLine("\n" + i); } Console.ReadLine(); } } |
Write C# program to print sum of digits enter by user.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int num, total; //Reading number Console.WriteLine("Enter any number: "); num = Convert.ToInt32(Console.ReadLine()); //Adding sum of digit in total variable for (total = 0; num > 0; num = num / 10) total = total + (num % 10); //Printing sum of digit Console.WriteLine("Sum of digits: "+ total); Console.ReadLine(); } } |
Write C# program to find sum of even numbers between 1 to n.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 | using System; using System.Collections.Generic; using System.Linq; using System.Text; public class csharpExercise { static void Main(string[] args) { int i, num, sum = 0; // Reading number Console.Write("Enter any number: "); num = Convert.ToInt32(Console.ReadLine()); for (i = 2; i <= num; i += 2) { //Adding current even number to sum variable sum += i; } Console.WriteLine("Sum of all even number between 1 to " + num + " = "+ sum); Console.ReadLine(); } } |
