Exercise 4

Added Exercise 4 to respository with README Files

Informatik_I/Exercise_4/Task_3/README.md

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+# Task
+
+Implement the following rounding function that rounds a 64-bit floating point number (type `double`) to the nearest 32-bit integer (type `int`). You may assume that the type `double` complies with the IEEE standard 754. The function is only required to work correctly if the nearest integer is in the value range of the type `int`, otherwise, the return value of the function is undefined.
+
+**Note: Usage of library rounding functions (standard or others) is not allowed.**
+
+```cpp
+// PRE: x is roundable to a number in the value range of type @int@
+// POST: return value is the integer nearest to x, or the one further
+// away from 0 if x lies right in between two integers.
+int round_number(double x);
+```
+
+Write your solution in `rounding.h`.
+
+_Hint_: In `C++`, when you convert a `float` or `double` to an `int`, the fractional part gets cut off (truncated). Think about how you can use the truncated number to solve the exercise.

Informatik_I/Exercise_4/Task_3/rounding.h

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+#pragma once
+
+// PRE: x is roundable to a number in the value range of type int
+// POST: return value is the integer nearest to x, or the one further
+//       away from 0 if x lies right in between two integers.
+int round_number(double x) {
+  int res;
+  if (x < 0)
+    res = x - 0.5;
+  else
+    res = x + 0.5;
+  return res;
+}