Add solution for Challenge 3 (#663)

Co-authored-by: go-interview-practice-bot[bot] <230190823+go-interview-practice-bot[bot]@users.noreply.github.com>

Author: kiramux

challenge-3/submissions/kiramux/solution-template.go

@@ -0,0 +1,79 @@
+package main
+
+import "fmt"
+
+type Employee struct {
+ID int
+Name string
+Age int
+Salary float64
+}
+
+type Manager struct {
+Employees []Employee
+}
+
+// AddEmployee adds a new employee to the manager's list.
+func (m *Manager) AddEmployee(e Employee) {
+// TODO: Implement this method
+m.Employees = append(m.Employees, e)
+}
+
+// RemoveEmployee removes an employee by ID from the manager's list.
+func (m *Manager) RemoveEmployee(id int) {
+// TODO: Implement this method
+size := len(m.Employees)
+ flag := -1
+for i := range m.Employees {
+ if m.Employees[i].ID == id {
+ flag = i
+ break
+ } 
+}
+if flag != -1 {
+ m.Employees[flag] = m.Employees[size-1]
+ m.Employees = m.Employees[:size-1]
+}
+}
+
+// GetAverageSalary calculates the average salary of all employees.
+func (m *Manager) GetAverageSalary() float64 {
+// TODO: Implement this method
+size := len(m.Employees)
+if size == 0 {
+ return 0
+}
+
+var sum float64
+for i := 0; i < size; i++ {
+ sum += m.Employees[i].Salary
+}
+avg := sum / float64(size)
+return avg
+}
+
+// FindEmployeeByID finds and returns an employee by their ID.
+func (m *Manager) FindEmployeeByID(id int) *Employee {
+// TODO: Implement this method
+for i := range m.Employees {
+ if m.Employees[i].ID == id {
+ return &(m.Employees[i])
+ } 
+}
+fmt.Println("Cannot find employee by ID: ", id)
+return nil
+}
+
+func main() {
+manager := Manager{}
+manager.AddEmployee(Employee{ID: 1, Name: "Alice", Age: 30, Salary: 70000})
+manager.AddEmployee(Employee{ID: 2, Name: "Bob", Age: 25, Salary: 65000})
+manager.RemoveEmployee(1)
+averageSalary := manager.GetAverageSalary()
+employee := manager.FindEmployeeByID(2)
+
+fmt.Printf("Average Salary: %f\n", averageSalary)
+if employee != nil {
+fmt.Printf("Employee found: %+v\n", *employee)
+}
+}