Introduction
In Kotlin, the Long
class represents a 64-bit signed integer. It is used for numerical values that require a larger range than the Int
class. The Long
class provides various methods to perform arithmetic operations, comparisons, and type conversions.
Table of Contents
- What is the
Long
Class? - Creating
Long
Values - Long Operations
- Long Functions
- Examples of
Long
- Real-World Use Case
- Conclusion
1. What is the Long Class?
The Long
class in Kotlin is a wrapper for the primitive long type. It provides methods and properties to work with 64-bit signed integer values. Long integers are used for numerical calculations that require a larger range than Int
.
Syntax
val myLong: Long = 123456789L
2. Creating Long Values
You can create Long
values using literals with an L
or l
suffix, or by converting other numeric types to Long
.
Example
fun main() {
val a: Long = 123456789L
val b = 987654321L
val c = "1234567890123456789".toLong()
println("a: $a, b: $b, c: $c")
}
3. Long Operations
Kotlin supports various operations on Long
values, including arithmetic and comparison operations.
Arithmetic Operations
+
(Addition)-
(Subtraction)*
(Multiplication)/
(Division)%
(Modulus)
Example
fun main() {
val a: Long = 10000000000L
val b: Long = 2000000000L
val sum = a + b
val difference = a - b
val product = a * b
val quotient = a / b
val remainder = a % b
println("Sum: $sum")
println("Difference: $difference")
println("Product: $product")
println("Quotient: $quotient")
println("Remainder: $remainder")
}
Comparison Operations
==
(Equal to)!=
(Not equal to)<
(Less than)>
(Greater than)<=
(Less than or equal to)>=
(Greater than or equal to)
Example
fun main() {
val a: Long = 10000000000L
val b: Long = 2000000000L
println("a == b: ${a == b}")
println("a != b: ${a != b}")
println("a < b: ${a < b}")
println("a > b: ${a > b}")
println("a <= b: ${a <= b}")
println("a >= b: ${a >= b}")
}
4. Long Functions
The Long
class provides several useful functions:
toByte()
: Converts the value to aByte
.toShort()
: Converts the value to aShort
.toInt()
: Converts the value to anInt
.toFloat()
: Converts the value to aFloat
.toDouble()
: Converts the value to aDouble
.toString()
: Converts the value to aString
.compareTo(other: Long)
: Compares this value with anotherLong
.
Example
fun main() {
val a: Long = 1234567890123456789L
println("toByte: ${a.toByte()}")
println("toShort: ${a.toShort()}")
println("toInt: ${a.toInt()}")
println("toFloat: ${a.toFloat()}")
println("toDouble: ${a.toDouble()}")
println("toString: ${a.toString()}")
println("compareTo 1000000000L: ${a.compareTo(1000000000L)}")
}
5. Examples of Long
Example 1: Calculating Factorial
This example demonstrates using Long
to calculate the factorial of a number.
fun factorial(n: Long): Long {
return if (n == 1L) n else n * factorial(n - 1)
}
fun main() {
val num = 20L
val result = factorial(num)
println("Factorial of $num is $result")
}
Output:
Factorial of 20 is 2432902008176640000
Explanation:
This example calculates the factorial of a given number using recursion with Long
values.
Example 2: Checking if a Number is Prime
This example demonstrates checking if a number is prime using Long
.
fun isPrime(n: Long): Boolean {
if (n <= 1L) return false
for (i in 2..n / 2) {
if (n % i == 0L) return false
}
return true
}
fun main() {
val num = 15485863L
if (isPrime(num)) {
println("$num is a prime number")
} else {
println("$num is not a prime number")
}
}
Output:
15485863 is a prime number
Explanation:
This example checks if a given number is prime by checking divisibility from 2 to half of the number using Long
values.
Example 3: Calculating Power of a Number
This example demonstrates calculating the power of a number using Long
.
fun power(base: Long, exponent: Long): Long {
if (exponent == 0L) return 1L
var result = 1L
for (i in 1..exponent) {
result *= base
}
return result
}
fun main() {
val base = 5L
val exponent = 3L
val result = power(base, exponent)
println("$base^$exponent is $result")
}
Output:
5^3 is 125
Explanation:
This example calculates the power of a number using a loop with Long
values.
6. Real-World Use Case: Calculating Compound Interest
In a real-world scenario, you might need to calculate the compound interest for an investment using Long
.
Example: Calculating Compound Interest
fun calculateCompoundInterest(principal: Long, rate: Float, time: Long, n: Long): Long {
val r = rate / 100
val amount = principal * Math.pow((1 + r / n).toDouble(), (n * time).toDouble())
return amount.toLong()
}
fun main() {
val principal = 1000000L // Principal amount in rupees
val rate = 8.0f // Annual interest rate in percentage
val time = 10L // Investment period in years
val n = 4L // Compounding frequency (quarterly)
val compoundInterest = calculateCompoundInterest(principal, rate, time, n)
println("Compound Interest: ?$compoundInterest")
}
Output:
Compound Interest: ?2219640
Explanation:
This example calculates the compound interest for an investment given the principal amount, annual interest rate, investment period, and compounding frequency using Long
values.
Conclusion
The Long
class in Kotlin provides a way to work with 64-bit signed integer values and perform various operations on them. It offers a range of functions to convert between different numeric types, compare values, and perform arithmetic operations. Understanding how to use the Long
class and its functions is essential for effective Kotlin programming, especially when dealing with large numerical values and calculations.
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