Step by Step solution about How to resolve the algorithm Loops/With multiple ranges step by step in the Kotlin programming language

The provided Kotlin code is a program that calculates the sum and product of a series of integers within specified ranges. Here's a detailed explanation of the code:

1. Custom 'pow' Function:

infix fun Int.pow(e: Int): Int {
   if (e == 0) return 1
   var prod = this
   for (i in 2..e) {
       prod *= this
   }
   return prod
}

This function defines a custom infix 'pow' operator that calculates the exponentiation of an integer. It uses a loop to repeatedly multiply the number by itself.

2. Main Function:

The code defines two versions of the 'main' function, which is the entry point of the program.

Version 1:

fun main(args: Array<String>) {
   // ...
}

Version 2:

fun main() {
   // ...
}

Both versions of the 'main' function do the same thing.

3. Variables:

The program initializes several integer variables, which are used as constants and boundaries for the ranges:

• x, y, z, one, three, seven: Constants used in the ranges.
• p: Calculated as 11 ^ 5 using the custom 'pow' operator.

4. 'process' Function:

fun process(j: Int) {
   sum += abs(j)
   if (abs(prod) < (1 shl 27) && j != 0) prod *= j
}

This function performs two operations:

• Adds the absolute value of j to the sum.
• Multiplies prod by j if the absolute value of prod is less than 2^27 and j is not 0.

5. Ranges and Iterations:

The code uses several ranges defined by the variables and the step values to iterate through a series of integers. Each iteration calls the 'process' function with the value of the iterator variable (j).

6. Calculations:

• The program calculates the sum of the absolute values of all the integers in the ranges.
• It also calculates the product of the non-zero integers in the ranges.

7. Printing the Results:

Finally, the program prints the calculated sum and prod to the standard output using System.out.printf.

8. Enhanced Version (Version 2):

The second version of the 'main' function uses an infix function called '^' for exponentiation and the 'flatten' function to combine multiple ranges into a single sequence. This version is slightly more concise and modern.

// Version 1.2.70

import kotlin.math.abs

infix fun Int.pow(e: Int): Int {
    if (e == 0) return 1
    var prod = this
    for (i in 2..e) {
        prod *= this
    }
    return prod
}

fun main(args: Array<String>) {
    var prod = 1
    var sum = 0
    val x = 5
    val y = -5
    val z = -2
    val one = 1
    val three = 3
    val seven = 7
    val p = 11 pow x
    fun process(j: Int) {
        sum += abs(j)
        if (abs(prod) < (1 shl 27) && j != 0) prod *= j
    }

    for (j in -three..(3 pow 3) step three) process(j)
    for (j in -seven..seven step x) process(j)
    for (j in 555..550-y) process(j)
    for (j in 22 downTo -28 step three) process(j)
    for (j in 1927..1939) process(j)
    for (j in x downTo y step -z) process(j)
    for (j in p..p + one) process(j)
    System.out.printf("sum  = % ,d\n", sum)
    System.out.printf("prod = % ,d\n", prod)
}


import kotlin.math.abs
import kotlin.math.pow

private infix fun Int.`^`(exponent: Int): Int = toDouble().pow(exponent).toInt()

fun main() {
    var prod = 1
    var sum = 0
    val x = 5
    val y = -5
    val z = -2
    val one = 1
    val three = 3
    val seven = 7
    val p = 11 `^` x

    for (j in sequenceOf(
        -three..(3 `^` 3) step three,
        -seven..seven step x,
        555..550-y,
        22 downTo -28 step three,
        1927..1939,
        x downTo y step -z,
        p..p + one
    ).flatten()) {
        sum += abs(j)
        if (abs(prod) < (2 `^` 27) && j != 0) prod *= j
    }
    System.out.printf("sum  = % ,d\n", sum)
    System.out.printf("prod = % ,d\n", prod)
}