1. implement a function double root(double a, double b, double c) which returns:
2. implement a function void root(double a, double b, double c, double& x1, double& x2) which assigns two solutions of quadratic equation to variables x1 and x2 . where a , b and c are real numbers. the 2 solutions are:
3. write the pre-condition and post-condition for two functions above (in questions 1 and 2).
4. implement a function void my_swap(int& a, int& b) . it swap two values of the actual parameters.
5. write a void function definition for a function called zero_both that has 2 reference parameters, both of which are variables of type int , and sets the values of both variables to 0 .
6. write a stub for function double totalprice(double single_price, int total_items) .
7. write a function int sum(int n) ; which will return the sum of 1+2+…+n where n is a positive integer.
8. write the pre-condition and post-condition of above function.
9. write an if statement to halt to program if the program fails to open a file. assume the file to be opened has name stats. dat .