Exercise 6

Added Exercise 6

Informatik_I/Exercise_6/Task_1/README.org

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+#+TITLE: Task 1: Const and reference types
+#+AUTHOR: JirR02
+
+/This task is a text based task. You do not need to write any program/C++ file: the answer should be written in main.md (and might include code fragments if questions ask for them)./
+
+*Note:* You can safely ignore any undefined behavior due to integer overflows.
+
+* Task
+
+Consider the following functions:
+
+1.
+
+   #+begin_src cpp
+int foo(int i) {
+    return ++i;
+}
+   #+end_src
+
+2.
+
+   #+begin_src cpp
+int foo(const int i) {
+    return ++i;
+}
+   #+end_src
+
+3.
+
+   #+begin_src cpp
+int foo(int& i) {
+    return ++i;
+}
+   #+end_src
+
+4.
+   
+   #+begin_src cpp
+int& foo(int i) {
+    return ++i;
+}
+   #+end_src
+
+5.
+
+   #+begin_src cpp
+const int& foo(int& i) {
+    return ++i;
+}
+   #+end_src
+
+For each function, answer the following questions:
+
+    a) Does the function attempt to modify const variables? If so, give the reason why (max. 15 words).
+
+If no, answer the following (otherwise put N/A):
+
+    b) Variable scopes: are the output and side effects of the function well-defined, i.e., free of undefined behavior? If not, give the reason why (max. 15 words).
+
+    c) If the answer in b) is yes, give the precise post condition for the corresponding function foo. In particular, indicate what side effects the function may have.
+
+* Solution
+
+#+begin_src md
+1.
+
+```c++
+int foo(int i) {
+    return ++i;
+}
+```
+
+a) Yes and no, if depends if the input is assigend to a constant or not but generally no.
+
+b) Yes
+
+c) `foo` returns the increment by 1 of `i`. The side effect of this function is, that the variable `i` is only accessible inside the function `foo`. To make `i` accessible, one has to use the function as follows: `int b = foo(i)`
+
+
+2.
+```c++
+int foo(const int i) {
+    return ++i;
+}
+```
+
+a) Yes, since `i` is defined as a constant variable the function foo increments `i`.
+
+b) N/A
+
+c) N/A
+
+
+3.
+
+```c++
+int foo(int& i) {
+    return ++i;
+}
+```
+
+a) Yes and no, it depends if the reference is assigned to a constant variable or not but generally no.
+
+b) Yes
+
+c) The variable `i` which is referenced to another variable outside of the function will be incremented. Since it's referenced the variable is not only accessible within the function.
+
+
+4.
+
+```c++
+int& foo(int i) {
+    return ++i;
+}
+```
+
+a) Yes and no, if depends if the input is assigend to a constant or not but generally no.
+
+b) Yes
+
+c) Since the whole function is a referenced, the variable which is inputted into the function will not be incremented. Instead the variable `i` will only be in scope of the function `foo` so as in task two, to use the function one has to use it as follows: `int b = foo(i);`
+
+5.
+
+```c++
+const int& foo(int& i) {
+    return ++i;
+}
+```
+
+a) Yes and no, if depends if the input is assigend to a constant or not but generally no.
+
+b) Yes
+
+c) This function will increment the input and return it as a constant.
+#+end_src
+
+-----
+
+Made by JirR02 in Switzerland 🇨🇭