develop a non-scientific calculator using C.
Your calculator should only solve summation, subtraction, division, product, square root and square expressions. Utilizing the math.h header for your program, your calculator should start by prompting the user to enter a two-operand mathematical equation (for example 3.74 + 22 or 35.32 - 6.2) just like how you would using a non-scientific calculator. Your program should then display the correct answer and the user will have the choice to either continue using the calculator with the current answer to perform further calculations or end the program. Your program should also have a help function to display all the functions of the calculator.