c++

Create a function whose inputs are 3 strings. Your function will return a string which is the concatenation of the three strings. (For example: the concatenation of the strings "abc", "def". and "ghi" is "abcdefghi".) Create a function called round, which rounds a double to the nearest integer. The function returns this integer. Create a function whose input is a string. Your function will create a new string from tile old one by changing all lower coos letters to upper case letters and vice versa. It leaves all other characters unchanged. Your function returns this string. Create a boolean function which can tell if a user has created a proper password. You consider a proper password to be between 8 and 16 characters long, contains at least one number, at least one lows case letter, at least one upper case letter, and no special characters. Create a function whose input is 2 strings (representing an existing filename and a new filename respectively). Your function will create the new file which is an exact replica of the existing file. Create a function whose inputs are an array of doubles and an integer representing the size of the array. The function returns the product of the entries in the array. Create a single function which "returns" both the average of 2 integer inputs and the product of the inputs. Create function declaration statements for the following situations: A function named calc which has 3 inputs: 2 doubles and an int, and 3 "outputs": one double and 2 ints. A function whose input is an of stream and has no return value. A function whose inputs are a character array of variable length and its size and whose return value is a string. Create a class definition representing an equation of a line y = mx + b (the variables m and b are what define the line). Constructors: y = 0 for 0 parameters, y = b for one parameter, y = mx + b for 2 parameters. Functions: slope() (returns slope of line), int() (returns y-int of line), xint() (returns x-int), at(x) (calculates y value at a specific x value), on(x, y) (returns true if (x, y) on the line, false otherwise), par(k) (returns a line parallel to your line with y-int k), perp(k) (returns a line perpendicular to your line with y-int k). Create the class definition for this class. Create the constructors and functions described above