Add solution for explizitesCasting.

io/myio.c

@@ -23,5 +23,20 @@ int getNumber(const char *text)
         while(getchar() != '\n') {} 
     } while(!wasSuccessful);
 
+    return number;
+}
+
+double getDoubleNumber(const char *text)
+{
+    double number = 0;
+    int wasSuccessful = 0;
+
+    do
+    {
+        printf("%s", text);
+        wasSuccessful = scanf("%lf", &number);
+        while(getchar() != '\n') {} 
+    } while(!wasSuccessful);
+
     return number;
 }

io/myio.h

@@ -3,5 +3,6 @@
 
 unsigned char getSingleChar();
 int getNumber(const char *text);
+double getDoubleNumber(const char *text);
 
 #endif