Fixed conflict.

source/exercises/w_sol/collections/2darrays.md

@@ -0,0 +1,44 @@
+---
+tags:
+  - datatypes/collections
+---
+
+# Two-Dimensional Arrays
+
+## Exercises
+
+#. Write a statement that creates a 2-dimensional rectangular array of `int` with 5 rows and 3 columns.
+
+    <details>
+    <summary>Solution</summary>
+
+    ```
+    int[,] matrix = new int[5, 3];
+    ```
+    </details>
+
+#. Write a statement that creates a 2-dimensional jagged array of `int` with 2 rows. The first row should contain an array containing 1, the second row should contain an array containing 2, 3.
+
+    <details>
+    <summary>Solution</summary>
+
+    ```
+    int[][] jaggedArray = new int[2][];
+    jaggedArray[0] = new int[1] { 1 };
+    jaggedArray[1] = new int [2]{ 2, 3};
+    ```
+
+#. Suppose we have a 2-dimensional rectangular array named `temp` that has been declared and initialized. How can we know the number of rows in this array?
+
+    <details>
+    <summary>Solution</summary>
+    By using the `GetLength` method: `temp.GetLength(0)` is the number of rows in the `temp` array.
+    </details>
+
+#. Suppose we have a 2-dimensional rectangular array named `temp` that has been declared and initialized. How can we know the number of elements in this array?
+
+    <details>
+    <summary>Solution</summary>
+    By using the `Length` field: `temp.Length` is the number of elements in the `temp` array.
+    We can also compute the product of `temp.GetLength(0)` and `temp.GetLength(1)`.
+    </details>

source/exercises/w_sol/io/index.md

@@ -1,3 +1,3 @@
 ---
-title: IO
----
+title: input / output
+---

source/exercises/w_sol/past/mcq.md

@@ -242,7 +242,6 @@ title: "Multiple Choice Questions (with solutions)"
     - [ ] Any number between 10 and 100 (both excluded)
     - [ ] Any number not between 10 and 100 (both excluded)
 
-
 #. What will be displayed by the following code?
 
     ```

source/exercises/w_sol/past/sortme.md

@@ -277,41 +277,7 @@ else {Console.WriteLie(“No”);}
 
 
 
-#. Assuming we have two **int** arrays of the same size, `firstA` and `secondA`, write a program that copies the content of `firstA` into `secondA`.
 
-    <details>
-    <summary>Solution</summary>
-
-    ```cs
-    for (int k =0; k < firstA.Length; k++)
-        secondA[k] = firstA[k];
-    ```
-    </details>
-
-#. Write a static method (header included) that takes as an argument an **int** array, and display on the screen the value of each element of that array.
-
-    <details>
-    <summary>Solution</summary>
-
-    ```cs
-    public static void p(int[] a){
-        foreach (int k in a) Console.WriteLine(k);
-    }
-    ```
-    </details>
-
-#. Write a static method (header included) that takes as an argument an **int** array, and stores the value 10 in each element of that array.
-
-    <details>
-    <summary>Solution</summary>
-
-    ```cs
-    public static void z(int[] a){
-        for (int j = 0; j < a.Length; j++) a[j] = 10;
-    }
-    ```
-    </details>  
-
 
 #. What sequence will appear on the output of this C# code? Which parameter of `SD(int[] A, int B)` method is passed by value? 
 

source/exercises/wo_sol/collections/1darrays.md

@@ -0,0 +1,296 @@
+<!--
+
+DO NOT EDIT THIS FILE
+
+Edit exercises/w_sol/collections/1darrays.md, and run
+make exercises/wo_sol/collections/1darrays.md
+instead.
+-->
+
+---
+tags:
+  - datatypes/collections
+---
+
+# One-Dimensional Arrays
+
+## Multiple Choices
+
+#. What is the correct way of creating an array of `int` of size 5 named `myArray`?
+
+    - [ ] `int[] myArray = new int[5];`
+    - [ ] `int[] myArray = int[5];`
+    - [ ] `int[5] myArray = new int[];`
+    - [ ] `int[4] myArray = new int[];`
+    - [ ] `int myArray = new int[5];`
+    - [ ] `int[] myArray = new int[4];`
+    - [ ] `int[] myArray = new int(5);`
+    - [ ] `int[] myArray = int[4];`
+
+#. Consider the following code:
+
+    ```
+    int[] grades = {10, 20, 5, 15};
+    Console.WriteLine(grades[2]);
+    ```
+
+    What will it display?
+
+    - [ ] 5
+    - [ ] Nothing
+    - [ ] 20
+    - [ ] 15
+    - [ ] grades
+    - [ ] grades[2]
+    - [ ] 10
+
+#. Consider the following code:
+
+    ```
+    char[] grades = {'A', 'B', 'C', 'D', 'F'};
+    int i = 0;
+    while(i < grades.Length){
+        i++;
+        Console.WriteLine(grades[i]);
+    }
+    ```
+
+    Something is wrong with it, can you tell what?
+
+    - [ ] There will be an "Index was outside the bounds of the array." error.
+    - [ ] The array is not properly initialized.
+    - [ ] The loop is infinite
+    - [ ] `grades.Length` is not declared.
+
+
+## Exercises
+
+### Syntax
+
+#. Write a statement that creates a 10-element `int` array named `numbers`.
+
+
+#. Write a statement that creates and initializes an array of `double` with the values 12.5, 89.0 and 3.24.
+
+
+#. In the following, what is the value of the size declarator? What is the value of the index?
+
+    ```
+    int[] numbers;
+    numbers = new int[8];
+    numbers[4] = 9;
+    ```
+
+
+#. What is "array bounds checking"? When does it happen?
+
+
+#. Is there an error with the following code? If you think there is one, explain it, otherwise draw the content of the `myIncomes` array once those statements have been executed.
+
+    ```
+    double[] myIncomes = new double[5];
+    myIncomes[1] = 3.5;
+    // No income on day two.
+    myIncomes[3] = 5.8;
+    myIncomes[4] = 0.5;
+    myIncomes[5] = 1.5;
+    ```
+
+
+#. What would be the size of the `test` array after the following statement has been executed?
+
+    `int[] test = {3, 5, 7, 0, 9};`
+
+
+#. What is wrong with the following array declaration?
+
+    ```
+    int[] books = new int[-1];
+    ```
+
+#. Suppose we have an array named `temp` that has been declared and initialized. How can we know the number of elements in this array?
+
+
+#. What is the value of `count` and the content of `number` once the following has been executed?
+
+    ```
+    int count=2;
+    int[] number={3, 5, 7};
+    number[count--] = 8;
+    number[count]--;
+    ```
+
+
+
+#. Describe what the following code would do.
+
+    ```
+    int[] record = { 3, 8, 11 };
+    int accumulator = 0;
+    foreach (int i in record)
+        accumulator += i;
+    ```
+
+
+### Displaying Arrays
+
+#. Write code that displays the first and last element of an array.
+
+
+#. What will be displayed at the screen by the following code?
+
+    ```
+    int[] values = new int[6];
+    for (int i = 0 ; i < 6 ; i++)
+        values[i] = (i * 2 );
+        
+    foreach (int j in values)
+        Console.WriteLine(j);
+    ```
+
+
+#. Suppose we are given an `int` array `dailyPushUp` with 7 elements. Write a piece of code that displays the value of the elements stored in the array `dailyPushUp`.
+
+
+#. Write code that displays every element in a `numbers` array of integers.
+
+
+#. Write code that displays every element in a `numbers` array of integers in reverse order.
+
+
+#. Write code that displays every other element in a `numbers` array of integers (that is, every even index).
+
+
+#. Given an array `numbers` and a variable `x`, write code that displays every value in `myArray` that is equal to or greater than `x`.
+
+
+#. Write code that displays every unique value of *a sorted* array `numbers`. This array could contain, for example, 1, 1, 1, 4, 4, 5, 8, 9, 11: values are increasing and can occur multiple times. In our example, the values 1, 4, 5, 8, 9 and 11.
+
+
+### Filling Arrays
+
+#. Given an array `myArray` and some value `x`, write code that sets the value of every array element to `x`.
+
+
+#. Given some positive number `n`, write code that first declares an array of length `n`, then sets its contents to sequentially increasing values 1, 2, 3, ..., n.
+
+
+#. Given an array of integers, and two integer variables `oldValue` and `newValue`; write code that replaces every occurrence of `oldValue` in the array with `newValue`.
+
+
+#. Write code that squares every value in an `myArray` integer array. For example, an array containing 2, 3, 4 would after the program contain 4, 9, 16.
+
+
+
+### Looking For Values
+
+#. Given an array `myArray` and a value `val`, write code that checks if `myArray` contains `val`. The result should be `true` if `val` occur in `myArray` and `false` otherwise.
+
+
+#. Given an array `myArray` and a variable `x`, write code that computes the number of times `x` occurs in `myArray`.
+
+
+#. Given an array `myArray` and two values `x` and `y`, write code that checks if `myArray` contains *either* `x` or `y`. The result should be `true` if `x` or `y` occur in `myArray` and `false` otherwise.
+
+
+#. Given an array `myArray` and two values `x` and `y`, write code that checks if `myArray` contains *both* values `x` and `y`. The result should be `true` when both values occur and `false` otherwise.
+
+
+#. Given an integer `myArray` and a strictly positive integer value `x`, find an array element whose value is largest while also being strictly less than `x` and display it, or display 0 if there is no such value.
+For example, in an array containing 1, 2, 6, 7, 3, 9 with x being 8, the solution is 7.
+
+
+#. Consider an array of `char`. Implement code to check if the array values form a palindrome, i.e., it reads the same way forwards and backwards.
+
+
+
+### Manipulating Two Arrays
+
+#. Assuming we have two `int` arrays of the same size, `firstA` and `secondA`, write a program that copies the content of `firstA` into `secondA`.
+
+
+
+#. Given two arrays `array1` and `array2`, write a program to determine if there exists a value that occurs in both arrays. If such value exists, the result should be `true` and `false` otherwise.
+
+
+
+#. Write a program that combines two `string` arrays called `array1` and `array2` into a single array containing first all the elements from `array1`, then all the elements from `array2`.
+
+
+#. Given two arrays `arrayA` and `arrayB`, write code to check if every element in `arrayB` occurs in `arrayA`, then display the result as `true` or `false`.
+
+
+### Methods
+
+#. Write a static method (header included) that takes as an argument an `int` array, and displays on the screen the value of each element of that array.
+
+
+#. Write a static method (header included) that takes as an argument an `int` array, and stores the value 10 in each element of that array.
+
+
+
+## Simple Algorithms
+
+#. Write a program that computes the sum of values stored in a `numbers` array of integers and displays it.
+
+
+#. Given an array of positive integers, count how many even values occur in that array.
+
+
+#. Write a program that computes the average of the elements in a `arrayP` numeric array.
+
+
+#. Write a program that finds the largest value in an integer array `arrayP`.
+
+
+#. Write a program that finds the smallest value in an integer array `arrayP`.
+
+
+#. Write a program that finds the *second* smallest value in an array of integers `arrayP`.
+
+
+#. Write code that finds the index of the first occurrence of a value `val` in an array `arrayP`. If the array does not contain the value, the result should be -1.
+
+
+#. Write code that finds the index of the last occurrence of a value in an array. If the array does not contain the value, the result should be -1.
+
+
+
+#. Write code to reverse the contents of an array `myArray`. For example, an array containing 1, 4, 3, 2, 5 should contain, after the program was executed, 5, 2, 3, 4, 1.
+
+
+## Wrap-Up Problems
+
+#. Declare and initialize three arrays:
+
+    - Choose different data type for each array,
+    - Make the arrays have different lengths: 3, 5, 10 elements respectively,
+    - Initialize each array with appropriate values of your choice (depends on the type).
+
+    After you have declared and initialized the arrays, display on the screen
+
+    - The first value from array 1 (0th index),
+    - The last value from array 2 (4th index),
+    - The first three values from array 3 (indexed 0 - 2).
+
+
+#. Consider this array of words:
+
+    ```
+    string[] words = {"voice", "effect", "day", "orange", "appliance", "fly", "cloud", "degree", "engine", "society"};
+    ```
+
+    Write code to display an answer to the following questions. If the solution requires looping, use **foreach** loop when possible. Otherwise, use a **for** loop.
+
+    #. Does words array contain "engine"? (true/false)
+    #. Does words array contain "day" at least 2 times? (true/false)
+    #. What is the position (index) of the word "society"? If it does not exist answer should be -1. Find the position of the first occurrence in case there are multiple matches.
+
+    After you have implemented your code, change the array contents and make sure your code still works and does not crash.
+
+    Here is another array of words to test your solution:
+
+    ```
+    string[] words = {"addition", "day", "start", "dock", "fowl", "fish", "seat", "day"};
+    ```
+