Code org

Author: Rajeev Kumar Singh

06-functions/01-function-declaration/main.go

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+package main
+
+import "fmt"
+
+func avg(x float64, y float64) float64 {
+	return (x + y) / 2
+}
+
+func main() {
+	x := 5.75
+	y := 6.25
+
+	result := avg(x, y)
+
+	fmt.Printf("Average of %.2f and %.2f = %.2f\n", x, y, result)
+}

06-functions/02-function-multiple-return-values/main.go

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+package main
+
+import (
+	"fmt"
+	"math"
+)
+
+func getStockPriceChange(prevPrice, currentPrice float64) (float64, float64) {
+	change := currentPrice - prevPrice
+	percentChange := (change / prevPrice) * 100
+	return change, percentChange
+}
+
+func main() {
+	prevStockPrice := 0.0
+	currentStockPrice := 100000.0
+
+	change, percentChange := getStockPriceChange(prevStockPrice, currentStockPrice)
+
+	if change < 0 {
+		fmt.Printf("The Stock Price decreased by $%.2f which is %.2f%% of the prev price\n", math.Abs(change), math.Abs(percentChange))
+	} else {
+		fmt.Printf("The Stock Price increased by $%.2f which is %.2f%% of the prev price\n", change, percentChange)
+	}
+}

06-functions/03-function-multiple-return-values-error/main.go

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+package main
+
+import (
+	"errors"
+	"fmt"
+	"math"
+)
+
+func getStockPriceChangeWithError(prevPrice, currentPrice float64) (float64, float64, error) {
+	if prevPrice == 0 {
+		err := errors.New("Previous price cannot be zero")
+		return 0, 0, err
+	}
+	change := currentPrice - prevPrice
+	percentChange := (change / prevPrice) * 100
+	return change, percentChange, nil
+}
+
+func main() {
+	prevStockPrice := 0.0
+	currentStockPrice := 100000.0
+
+	change, percentChange, err := getStockPriceChangeWithError(prevStockPrice, currentStockPrice)
+
+	if err != nil {
+		fmt.Println("Sorry! There was an error: ", err)
+	} else {
+		if change < 0 {
+			fmt.Printf("The Stock Price decreased by $%.2f which is %.2f%% of the prev price\n", math.Abs(change), math.Abs(percentChange))
+		} else {
+			fmt.Printf("The Stock Price increased by $%.2f which is %.2f%% of the prev price\n", change, percentChange)
+		}
+	}
+}

06-functions/04-function-named-return-values/main.go

@@ -0,0 +1,25 @@
+package main
+
+import (
+	"fmt"
+	"math"
+)
+
+func getNamedStockPriceChange(prevPrice, currentPrice float64) (change, percentChange float64) {
+	change = currentPrice - prevPrice
+	percentChange = (change / prevPrice) * 100
+	return change, percentChange
+}
+
+func main() {
+	prevStockPrice := 100000.0
+	currentStockPrice := 90000.0
+
+	change, percentChange := getNamedStockPriceChange(prevStockPrice, currentStockPrice)
+
+	if change < 0 {
+		fmt.Printf("The Stock Price decreased by $%.2f which is %.2f%% of the prev price\n", math.Abs(change), math.Abs(percentChange))
+	} else {
+		fmt.Printf("The Stock Price increased by $%.2f which is %.2f%% of the prev price\n", change, percentChange)
+	}
+}

06-functions/05-blank-identifier/main.go

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+package main
+
+import (
+	"fmt"
+	"math"
+)
+
+func getStockPriceChange(prevPrice, currentPrice float64) (float64, float64) {
+	change := currentPrice - prevPrice
+	percentChange := (change / prevPrice) * 100
+	return change, percentChange
+}
+
+func main() {
+	prevStockPrice := 80000.0
+	currentStockPrice := 120000.0
+
+	change, _ := getStockPriceChange(prevStockPrice, currentStockPrice)
+
+	if change < 0 {
+		fmt.Printf("The Stock Price decreased by $%.2f\n", math.Abs(change))
+	} else {
+		fmt.Printf("The Stock Price increased by $%.2f\n", change)
+	}
+}

07-arrays/01-array-declaration/main.go

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+package main
+
+import "fmt"
+
+func main() {
+	var x [5]int // An array of 5 integers
+	fmt.Println(x)
+
+	var y [8]string // An array of 8 strings
+	fmt.Println(y)
+
+	var z [3]complex128 // An array of 3 complex numbers
+	fmt.Println(z)
+
+	// By default, all the array elements are assigned the zero value of the array type.
+	// For example, if we declare an integer array, all the elements will be initialized with zero.
+	// If we declare a string array, all the elements will be initialized with an empty string, and so on.
+}

07-arrays/02-array-indexing/main.go

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+package main
+
+import "fmt"
+
+func main() {
+	var x [5]int // An array of 5 integers
+
+	x[0] = 100
+	x[1] = 101
+	x[3] = 103
+	x[4] = 105
+
+	fmt.Printf("x[0] = %d, x[1] = %d, x[2] = %d\n", x[0], x[1], x[2])
+	fmt.Println("x = ", x)
+}

07-arrays/03-array-initialization/main.go

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+package main
+
+import "fmt"
+
+func main() {
+	// Declaring and initializing an array at the same time
+	var a = [5]int{2, 4, 6, 8, 10}
+	fmt.Println(a)
+
+	// Short hand declaration for declaring and initializing an array
+	b := [5]int{2, 4, 6, 8, 10}
+	fmt.Println(b)
+
+	// You don't need to initialize all the elements of the array.
+	// The un-initialized elements will be assigned the zero value of the corresponding array type
+	c := [5]int{2}
+	fmt.Println(c)
+
+	// Letting Go compiler infer the length of the array
+	d := [...]int{3, 5, 7, 9, 11, 13, 17}
+	fmt.Println(d)
+}

07-arrays/04-array-value-types/main.go

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+package main
+
+import "fmt"
+
+func main() {
+	a1 := [5]string{"English", "Japanese", "Spanish", "French", "Hindi"}
+	a2 := a1 // A copy of the array `a1` is assigned to `a2`
+
+	a2[1] = "German"
+
+	fmt.Println("a1 = ", a1) // The array `a1` remains unchanged
+	fmt.Println("a2 = ", a2)
+}

07-arrays/05-array-iteration/array_iteration.go

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+package main
+
+import "fmt"
+
+func main() {
+	// Iterating over and Array and printing its elements
+	names := [3]string{"Mark Zuckerberg", "Bill Gates", "Larrt Page"}
+
+	for i := 0; i < len(names); i++ {
+		fmt.Println(names[i])
+	}
+
+	// Finding the Sum of an Array
+	a := [4]float64{3.5, 7.2, 4.8, 9.5}
+	sum := float64(0)
+
+	for i := 0; i < len(a); i++ {
+		sum = sum + a[i]
+	}
+
+	fmt.Printf("Sum of all the elements in array  %v = %f\n", a, sum)
+}

07-arrays/06-array-iteration-range/main.go

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+package main
+
+import "fmt"
+
+func main() {
+	// Iterating over an array using range form of for loop
+	daysOfWeek := [7]string{"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"}
+
+	for index, value := range daysOfWeek {
+		fmt.Printf("Day %d of week = %s\n", index, value)
+	}
+
+	// Finding the sum of an array
+	a := [4]float64{3.5, 7.2, 4.8, 9.5}
+	sum := float64(0)
+
+	for _, value := range a {
+		sum = sum + value
+	}
+
+	fmt.Printf("Sum of all the elements in array %v = %f\n", a, sum)
+}

07-arrays/07-multi-dimensional-array/main.go

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+package main
+
+import "fmt"
+
+func main() {
+	a := [2][2]int{
+		{3, 5},
+		{7, 9}, // This comma is necessary
+	}
+	fmt.Println(a)
+
+	// Just like 1D arrays, you don't need to initialize all the elements in a multi-dimensional array.
+	// Un-initialized array elements will be assigned the zero value of the array type
+	b := [3][4]float64{
+		{1, 3},
+		{4.5, -3, 7.4, 2},
+		{6, 2, 11},
+	}
+	fmt.Println(b)
+}

08-slices/01-create-slice/main.go

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+package main
+
+import "fmt"
+
+func main() {
+	// Creating a slice using a slice literal
+	var s = []int{3, 5, 7, 9, 11, 13, 17} // Creates an array, and returns a slice reference to the array
+
+	// Short hand declaration
+	t := []int{2, 4, 8, 16, 32, 64}
+
+	fmt.Println("s = ", s)
+	fmt.Println("t = ", t)
+}

08-slices/02-create-slice-from-array/main.go

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+package main
+
+import "fmt"
+
+func main() {
+	var a = [5]string{"Alpha", "Beta", "Gamma", "Delta", "Epsilon"}
+
+	// Creating a slice from the array
+	var s []string = a[1:4]
+
+	fmt.Println("Array a = ", a)
+	fmt.Println("Slice s = ", s)
+
+	/*
+		low and high parameters are optional in a[low:high]
+		The default value for low is 0, and high is the length of the slice.
+	*/
+	slice1 := a[1:4]
+	slice2 := a[:3]
+	slice3 := a[2:]
+	slice4 := a[:]
+
+	fmt.Println("slice1 = ", slice1)
+	fmt.Println("slice2 = ", slice2)
+	fmt.Println("slice3 = ", slice3)
+	fmt.Println("slice4 = ", slice4)
+}

08-slices/03-create-slice-from-another-slice/main.go

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+package main
+
+import "fmt"
+
+func main() {
+	cities := []string{"New York", "London", "Chicago", "Beijing", "Delhi", "Mumbai", "Bangalore", "Hyderabad", "Hong Kong"}
+
+	asianCities := cities[3:]
+	indianCities := asianCities[1:5]
+
+	fmt.Println("cities = ", cities)
+	fmt.Println("asianCities = ", asianCities)
+	fmt.Println("indianCities = ", indianCities)
+}

08-slices/04-slice-modify/main.go

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+package main
+
+import "fmt"
+
+func main() {
+	a := [7]string{"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"}
+
+	slice1 := a[1:]
+	slice2 := a[3:]
+
+	fmt.Println("------- Before Modifications -------")
+	fmt.Println("a  = ", a)
+	fmt.Println("slice1 = ", slice1)
+	fmt.Println("slice2 = ", slice2)
+
+	slice1[0] = "TUE"
+	slice1[1] = "WED"
+	slice1[2] = "THU"
+
+	slice2[1] = "FRIDAY"
+
+	fmt.Println("\n-------- After Modifications --------")
+	fmt.Println("a  = ", a)
+	fmt.Println("slice1 = ", slice1)
+	fmt.Println("slice2 = ", slice2)
+}

08-slices/05-slice-length-capacity/main.go

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+package main
+
+import "fmt"
+
+func main() {
+	/*
+		The length of the slice is the number of elements in the slice.
+		The capacity is the number of elements in the underlying array starting from the first element in the slice.
+	*/
+	a := [6]int{10, 20, 30, 40, 50, 60}
+	s := a[1:4]
+
+	fmt.Printf("s = %v, len = %d, cap = %d\n", s, len(s), cap(s))
+}

08-slices/06-slice-extend-capacity/main.go

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+package main
+
+import "fmt"
+
+func main() {
+	s := []int{10, 20, 30, 40, 50, 60, 70, 80, 90, 100}
+	fmt.Println("Original Slice")
+	fmt.Printf("s = %v, len = %d, cap = %d\n", s, len(s), cap(s))
+
+	s = s[1:5]
+	fmt.Println("\nAfter slicing from index 1 to 5")
+	fmt.Printf("s = %v, len = %d, cap = %d\n", s, len(s), cap(s))
+
+	s = s[:8]
+	fmt.Println("\nAfter extending the length")
+	fmt.Printf("s = %v, len = %d, cap = %d\n", s, len(s), cap(s))
+
+	s = s[2:]
+	fmt.Println("\nAfter dropping the first two elements")
+	fmt.Printf("s = %v, len = %d, cap = %d\n", s, len(s), cap(s))
+}