exam-01: first 3 exercises

subjects/insertion_sort/README.md

@@ -14,10 +14,11 @@ The insertion sort algorithm:
 
 Here is a visual example of sorting a slice step by step using the insertion sort algorithm.
 
-![](Insertion-Sort-demo.jpg)
+![image.png](Insertion-Sort-demo.png)
+
 **Figure 1** - Step by step execution of the algorithm insertion sort
 
-- Implement the algorithm insertion sort by creating a function `insertion_sort(slice, steps)` that executes the iterations of the algorithm the number of steps indicated by the parameter `steps`. See the [Usage](#usage) for more information.
+- Implement the algorithm insertion sort by creating a function `insertion_sort(slice, steps)` that executes the iterations of the algorithm the number of steps indicated by the parameter `steps`. See the **Usage** for more information.
 
 ### Expected Function
 
@@ -32,17 +33,17 @@ Here is a possible program to test your function
 
 ```rust
 fn main() {
-	let mut target = [5, 3, 7, 2, 1, 6, 8, 4];
+    let mut target = [5, 3, 7, 2, 1, 6, 8, 4];
-	// executes the first iteration of the algorithm
+    // executes the first iteration of the algorithm
-	insertion_sort(&mut target, 1);
+    insertion_sort(&mut target, 1);
-	println!("{:?}", target);
+    println!("{:?}", target);
-
+
-	let mut target = [5, 3, 7, 2, 1, 6, 8, 4];
+    let mut target = [5, 3, 7, 2, 1, 6, 8, 4];
-	let len = target.len();
+    let len = target.len();
-	// executes len - 1 iterations of the algorithm
+    // executes len - 1 iterations of the algorithm
-	// i.e. sorts the slice
+    // i.e. sorts the slice
-	insertion_sort(&mut target, len - 1);
+    insertion_sort(&mut target, len - 1);
-	println!("{:?}", target);
+    println!("{:?}", target);
 }
 ```
 

subjects/matrix_transposition_4by3/README.md

@@ -8,11 +8,11 @@
 
 - Note:
 
-	- The transpose of a matrix `A` is the matrix `A'` where `A'`'s columns are `A`'s row and the rows are the columns:
+  - The transpose of a matrix `A` is the matrix `A'` where `A'`'s columns are `A`'s row and the rows are the columns:
 
 Example:
 
-```
+```console
 ( a b c )   __ transposition __>   ( a d g j )
 ( d e f )                          ( b e h k )
 ( g h i )                          ( c f i l )
@@ -25,22 +25,22 @@ Example:
 
 ### Notions
 
-[Chapter 7]( https://doc.rust-lang.org/stable/book/ch07-03-paths-for-referring-to-an-item-in-the-module-tree.html )
+[Chapter 7](https://doc.rust-lang.org/stable/book/ch07-03-paths-for-referring-to-an-item-in-the-module-tree.html)
 
 ### Expected Function and Structs
 
 ```rust
 pub struct Matrix4by3(
-	pub (i32, i32, i32),
+    pub (i32, i32, i32),
-	pub (i32, i32, i32),
+    pub (i32, i32, i32),
-	pub (i32, i32, i32),
+    pub (i32, i32, i32),
-	pub (i32, i32, i32),
+    pub (i32, i32, i32),
 );
 
 pub struct Matrix3by4(
-	pub (i32, i32, i32, i32),
+    pub (i32, i32, i32, i32),
-	pub (i32, i32, i32, i32),
+    pub (i32, i32, i32, i32),
-	pub (i32, i32, i32, i32),
+    pub (i32, i32, i32, i32),
 );
 
 pub fn transpose(m: Matrix4by3) -> Matrix3by4 {
@@ -49,17 +49,17 @@ pub fn transpose(m: Matrix4by3) -> Matrix3by4 {
 
 ### Usage
 
-Here is a posible program to test your function
+Here is a possible program to test your function
 
 ```rust
 fn main() {
-	let matrix = Matrix4by3((1, 2, 3), (4, 5, 6), (7, 8, 9), (10, 11, 12));
+    let matrix = Matrix4by3((1, 2, 3), (4, 5, 6), (7, 8, 9), (10, 11, 12));
     println!("Original matrix {:?}", matrix);
     println!("Transpose matrix {:?}", transpose(matrix));
 }
 ```
 
-And it's output:
+And its output:
 
 ```console
 student@ubuntu:~/[[ROOT]]/test$ cargo run

subjects/reverse_it/README.md

@@ -8,7 +8,9 @@ just add the char `-` to the beginning of the string.
 ### Expected Functions
 
 ```rust
-fn reverse_it(v: i32) -> String {}
+pub fn reverse_it(v: i32) -> String {
+
+}
 ```
 
 ### Usage

subjects/rpn/README.md

@@ -2,20 +2,16 @@
 
 ### Instructions
 
-Write a program that takes a `string` which contains an equation written in
+Write a program that takes a `string` which contains an equation written in `Reverse Polish Notation` (RPN) as its first argument,
-`Reverse Polish Notation` (RPN) as its first argument, that evaluates the equation, and that
+that evaluates the equation, and that prints the result on the standard output followed by a newline (`'\n'`).
-prints the result on the standard output followed by a newline (`'\n'`).
 
-`Reverse Polish Notation` is a mathematical notation in which every operator
+`Reverse Polish Notation` is a mathematical notation in which every operator follows all of its operands. In RPN,
-follows all of its operands. In RPN, every operator encountered evaluates the
+every operator encountered evaluates the previous 2 operands, and the result of this operation then becomes the first of
-previous 2 operands, and the result of this operation then becomes the first of
+the two operands for the subsequent operator. Operands and operators must be spaced by at least one space.
-the two operands for the subsequent operator. Operands and operators must be
-spaced by at least one space.
 
 The following operators must be implemented : `+`, `-`, `*`, `/`, and `%`.
 
-If the `string` is not valid or if there is not exactly one argument, `Error` must be printed
+If the `string` is not valid or if there is not exactly one argument, `Error` must be printed on the standard output followed by a newline.
-on the standard output followed by a newline.
 If the `string` has extra spaces it is still considered valid.
 
 All the given operands must fit in a `int`.
@@ -30,7 +26,7 @@ Examples of formulas converted in RPN:
 
 Here is how to evaluate a formula in RPN:
 
-```
+```console
 1 2 * 3 * 4 -
 2 3 * 4 -
 6 4 -
@@ -39,7 +35,7 @@ Here is how to evaluate a formula in RPN:
 
 Or:
 
-```
+```console
 3 1 2 * * 4 -
 3 2 * 4 -
 6 4 -
@@ -69,5 +65,5 @@ Error
 $ cargo run "     1      3 * 2 -"
 1
 $ cargo run "     1      3 * ksd 2 -"
-Error```
+Error
-````
+```