Resolução Parcial.

Tasks/HelpClasses/Repository.cs

@@ -5,7 +5,7 @@ namespace Tasks.HelpClasses
 {
     public class Repository
     {
-        public List<Student> Students;
+        public List<student> Students;
         public List<Product> Products;
 
         public Repository()
@@ -14,22 +14,22 @@ public Repository()
             Products = GetProducts();
         }
 
-        private static List<Student> GetStudents()
+        private static List<student> GetStudents()
         {
-            List<Student> students = new List<Student>();
-
-            students.Add(new Student(1, $"Student1", new DateTime(2020, 1, 1)));
-            students.Add(new Student(2, $"Student2", new DateTime(2010, 1, 1)));
-            students.Add(new Student(3, $"Student3", new DateTime(2011, 1, 1)));
-            students.Add(new Student(4, $"Student4", new DateTime(2012, 1, 1)));
-            students.Add(new Student(5, $"Student5", new DateTime(2013, 1, 1)));
-            students.Add(new Student(6, $"Student6", new DateTime(2014, 1, 1)));
-            students.Add(new Student(7, $"Student7", new DateTime(2015, 1, 1)));
-            students.Add(new Student(8, $"Student8", new DateTime(2016, 1, 1)));
-            students.Add(new Student(9, $"Student9", new DateTime(2017, 1, 1)));
-            students.Add(new Student(10, $"Student10", new DateTime(2018, 1, 1)));
-            students.Add(new Student(11, $"Student11", new DateTime(2019, 1, 1)));
-            students.Add(new Student(12, $"Student12", new DateTime(2020, 10, 31)));
+            List<student> students = new List<student>();
+
+            students.Add(new student(1, $"Student1", new DateTime(2020, 1, 1)));
+            students.Add(new student(2, $"Student2", new DateTime(2010, 1, 1)));
+            students.Add(new student(3, $"Student3", new DateTime(2011, 1, 1)));
+            students.Add(new student(4, $"Student4", new DateTime(2012, 1, 1)));
+            students.Add(new student(5, $"Student5", new DateTime(2013, 1, 1)));
+            students.Add(new student(6, $"Student6", new DateTime(2014, 1, 1)));
+            students.Add(new student(7, $"Student7", new DateTime(2015, 1, 1)));
+            students.Add(new student(8, $"Student8", new DateTime(2016, 1, 1)));
+            students.Add(new student(9, $"Student9", new DateTime(2017, 1, 1)));
+            students.Add(new student(10, $"Student10", new DateTime(2018, 1, 1)));
+            students.Add(new student(11, $"Student11", new DateTime(2019, 1, 1)));
+            students.Add(new student(12, $"Student12", new DateTime(2020, 10, 31)));
 
             return students;
         }

Tasks/HelpClasses/Student.cs

@@ -2,9 +2,9 @@
 
 namespace Tasks.HelpClasses
 {
-    public class Student
+    public class student
     {
-        public Student(int id, string name, DateTime birth)
+        public student(int id, string name, DateTime birth)
         {
             Id = id;
             Name = name;

Tasks/Task1.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Linq;
 
 namespace Tasks
 {
@@ -7,6 +8,10 @@ public class Task1
         /*
          * Dada a lista de inteiros, retorne o maior número da lista         
          */
-        public static int? GetMax(List<int> list) { }
+        public static int? GetMax(List<int> list) {
+            var valmax = list.Max();
+            return valmax;
+        }
     }
 }
+

Tasks/Task2.cs

@@ -1,4 +1,7 @@
-namespace Tasks
+using System.Linq;
+using System.Text.RegularExpressions;
+
+namespace Tasks
 {
     public class Task2
     {
@@ -20,6 +23,41 @@ public class Task2
          * 3 - abc1324
          * 4 - az111W
          */
-        public static bool CheckInput(string input) { }
+        public static bool CheckInput(string input)
+        {
+
+            int upcase = 0;
+            int lowcase = 0;
+            int num = 0;
+            bool result = false;
+
+
+            for (int i = 0; i < input.Length; i++)
+            {
+                char ch = input[i];
+                if (ch >= 'A' && ch <= 'Z')
+                    upcase++;
+                else if (ch >= 'a' && ch <= 'z')
+                    lowcase++;
+                else if (ch >= '0' && ch <= '9')
+                    num++;
+                if (upcase >= 3)
+                {
+                    if (lowcase >= 1)
+                    {
+                        if (num >= 4)
+                        {
+                            result = true;
+                        }
+                    }
+                }
+                else
+                    result = false;
+            }return result;
+        }
     }
 }
+
+
+
+

Tasks/Task3.cs

@@ -8,6 +8,20 @@ public class Task3
          * Dada a lista de inteiros, retorne o somatório de todos os itens com valor POSITIVO da lista     
          * LEMBRANDO que 0 (zero) NÃO é um número positivo
          */
-        public static int GetSum(List<int> list) { }
-    }
+        public static int GetSum(List<int> list)
+        {
+
+            int sum = 0;
+            foreach (int item in list)
+            {
+                if (item > 0) { 
+                    sum = item +sum;
+
+
+            }
+
+        }
+            return sum;
+        }
 }
+    }

Tasks/Task4.cs

@@ -1,4 +1,6 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
+using System.Linq;
 using Tasks.HelpClasses;
 
 namespace Tasks
@@ -9,6 +11,15 @@ public class Task4
          * Desenvolva um método que retorne todos os estudantes do Repositório que nasceram em 2020      
          * Dica: A classe Repository possui as informções dos Students
          */
-        public static List<Student> GetStudentsByBirth() { }
+        public static List<student> GetStudentsByBirth()
+        {
+            var repository = new Repository();
+            List<student> students = new List<student>();
+            var result = Enumerable.Range(0, students.Count)
+             .Select(id => students[id].Birth.Year == 2020)
+             .ToList();
+            return result;
+
+        }
     }
 }

Tasks/Task5.cs

@@ -6,6 +6,28 @@ public class Task5
          *Crie um método que receba um inteiro e retorne "impar" caso seja impar e "par" caso seja par
          *Caso o número seja 0 (zero), retorne "zero"
          */
-        public static string GetEvenOrOdd(int number) { }
+        public static string GetEvenOrOdd(int number)
+        {
+            string result = "";
+
+            if (number % 2 == 0)
+            {
+                result = ("par");
+            }
+
+
+
+            if (number % 2 != 0)
+            {
+                result = ("impar");
+            }
+
+            if (number == 0)
+            {
+                result = ("zero");
+            }
+
+            return result;
+        }
     }
 }

Tasks/Task6.cs

@@ -15,6 +15,26 @@ public class Task6
          * 0.333333
          * 0.166667
          */
-        public static List<decimal> GetRatios(List<int> numbers) { }
+        public static List<decimal> GetRatios(List<int> numbers) {
+            int i = 0;
+            int negnum = 0;
+            int zeronum = 0;
+            int posnum = 0;
+            for (i = 0; i <= numbers.Count; i++)
+            {
+                if (numbers[i] > 0) 
+                 posnum = posnum / negnum / zeronum;
+                numbers.Add(posnum);
+                if (numbers[i] < 0) 
+                negnum = negnum / posnum / zeronum;
+                numbers.Add(negnum);
+                if (numbers[i] == 0) 
+                 zeronum = zeronum / negnum / posnum;
+                numbers.Add(zeronum);
+
+            }
+            return numbers.ConvertAll(x => (decimal)x);
+
+        }
     }
 }

Tasks/Task7.cs

@@ -8,20 +8,25 @@ public class Task7
          * Desenvolma um método que retorne o nome dos produtos que estão com estoque zerado
          * Dica: A classe Repository possui as informções dos Products
          */
-        public static List<string> GetProductsOutOfStock() { }
-
+        public static List<string> GetProductsOutOfStock() {
+            return null;
+        }
         /*
         * Desenvolma um método que retorne a soma total das quantidades de estoque dos itens
         * Dica: A classe Repository possui as informções dos Products
         */
-        public static int GetSumStock() { }
-
+        public static int GetSumStock()
+        {
+            return 0;
+        }
         /*
          * Crie um método que verifique, dado Id e quantidade solicitada do produto
          * se o mesmo possui quantidade em estoque para venda
          * Dica: A classe Repository possui as informções dos Products
          * 
          */
-        public static bool IsSalePossible(int productId, int orderQuantity) { }
+        public static bool IsSalePossible(int productId, int orderQuantity) {
+            return false;
+        }
     }
 }

Tasks/Tasks.csproj

@@ -59,6 +59,7 @@
   </ItemGroup>
   <ItemGroup>
     <None Include="App.config" />
+    <None Include="packages.config" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
 </Project>

Tasks/packages.config

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<packages>
+  <package id="System.Collections" version="4.3.0" targetFramework="net472" />
+</packages>