c++ program using arrays and math formula

Define two arrays of floats (both of size 100). Fill both arrays from the user (keyboard) then do the following: 1- Determine whether both arrays are equal (have the same elements inside). 2- Reverse the values in the first array.
Ex: If the array has the elements: 10, 20, 30, 50, 15, 60 The array will become: 60, 15, 50, 30, 20, 10
3- Find the standard deviation of the elements in the first array

4- Read an integer value y from the user then count the number of times the value y appears in the array. Note that the value may not be in the array (appears zero times)

** without using math library please .

Thanks <3 .