add initial c, cpp files

cpp/exercism/01-basics/about.md

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+# About
+
+To set off the C++ journey we are starting with variables, function calls, and comments.
+
+## Comments
+
+Comments come in two flavors: single- and multi-line.
+Everything that comes after `//` on the same line is ignored by the compiler.
+Multi-line comments are also known as C-style comments.
+They are surrounded by `/*` and `*/`.
+Anything that comes between these will be ignored as well.
+
+## Variables
+
+C++ is a typed language.
+All types need to be known at compile time, and you generally need to state them explicitly.
+A variable's type cannot change.
+An integer variable with the name `years` can be declared like this:
+
+```cpp
+int years;
+```
+
+It is good practice to initialize variables upon declaration.
+C++ offers different mechanisms to do so.
+The version with the curly braces is more in line with modern C++, but the equal-sign version is also very common.
+
+```cpp
+int tomatoes{80};
+int potatoes = 40;
+```
+
+~~~~exercism/caution
+C++ does allow using uninitialized variables.
+Until the variable is deliberately set, it is undefined and might contain anything.
+To avoid used-before-set errors and undefined behavior it is adviseable to **always initialize**.
+Undefined behavior can crash your program at the worst possible moment, while it was running fine previously.
+It cannot be stressed enough: avoid undefined behavior at all cost.
+~~~~
+
+## Arithmetic Operations
+
+Arithmetic operators like `*`, `+`, or `-` can be part of an expression like `3 * 2` or `tomatoes + potatoes`.
+
+## Updating Variables
+
+You can reassign variables, as long as they keep their type:
+
+```cpp
+tomatoes = tomatoes - 5; // tomatoes is now 75
+potatoes = (32 * 2) + 11; // potatoes is now 75 as well
+```
+
+## Functions
+
+Functions have a name, a return type and a (possibly empty) parameter list.
+An example of a function named `always_fortyseven` that would always return 47 would look like this:
+
+```cpp
+int always_fortyseven() {
+    return 47;
+}
+```
+
+Here is `vip_fee`, which has one parameter:
+```cpp
+int vip_fee(int standard_fee) {
+    /*
+    vip_fee calculates the vip fee based on the standard_fee.
+    */
+    int vip_multi{3};
+    return standard_fee * vip_multi;
+}
+```
+
+Or `total_fee`, a function with three parameters and a call to another function.
+
+```cpp
+int total_fee(int vips, int adults, int kids) {
+    /*
+    total_fee calculates the total price for a group of VIP and adult guests with kids.
+    Kids get a flat discount on the standard fee.
+    VIP guest fees are calculated by calling vip_fee.
+    */
+    int standard_fee{30};
+    int kids_discount{15};
+
+    int kids_total_fee = kids  * (standard_fee - kids_discount);
+    int vips_total_fee = vips * vip_fee(standard_fee);
+    int adult_total_fee = adults * standard_fee;
+
+    return vips_total_fee + adult_total_fee + kids_total_fee;
+}
+```
+
+Functions in C++ do not return the value of the last statement like in some other languages.
+The `return` keyword is required for the code to compile.
+
+### Whitespace
+
+Whitespace is used for formatting source code and includes spaces, tabs, or newlines.
+As the compiler ignores unnecessary whitespace, you can use it to structure your code.
+Smart use of whitespace can improve the readability of your code.
+There are different formatting standards, but these are all conventional and not enforced by the compiler.
+
+```cpp
+// Formatting makes it easier to find bugs
+
+int eggs_yolks =  3;
+int      yeast = 15;
+
+int flour=500;int sugar=200;// compact, but difficult to read
+```