Armstrong Number in Swift Programming Language

Example to check whether an integer (entered by the user) is an Armstrong number or not using while loop and if…else statement.

A positive integer is called an Armstrong number of order n if

abcd = a pow n + b pow n + c pow n .....so on to n pow n 

In case of an Armstrong number of 3 digits, the sum of cubes of each digits is equal to the number itself. For example:

153 = 1 * 1 * 1 + 5 * 5 * 5 + 3 * 3 * 3  ../// 153 is Armstrong number 

Example #1: Check Armstrong Number of three digits

func checkAmstrongNumber(num:Int) -> String {


    var sum = 0


    var tempNum = num


    var reminder = 0


    while tempNum != 0  {


        reminder = tempNum % 10


        sum = sum + reminder * reminder * reminder


        tempNum /= 10


        if sum > num {break}


    }


    if sum == num {


        return "Yes"


    }


    return "No"


}


let numAm = 153


let resultAm = checkAmstrongNumber(num:numAm)


print(resultAm)

Output

Example #2: Check Armstrong Number of n digits

func checkAmstrongNumber(num:Int) -> String {

    var sum = 0

    var tempNum = num

    var reminder = 0

    let digits = String(num).count

    while tempNum != 0  {

        reminder = tempNum % 10

        sum = sum + Int(pow(Double(reminder), Double(digits)))

        tempNum /= 10

        if sum > num {break}

    }

    if sum == num {

        return "Yes"

    }

    return "No"

}

let numAm = 1634

let resultAm = checkAmstrongNumber(num:numAm)

print(resultAm)

Output

In this program, the number of digits of an integer is calculated first and stored in n variable. And, the pow() function is used to compute the power of individual digits in each iteration of the while loop.

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