Write a C++ function named is ValidReal() that checks for a double-precision number. This kind of number can have an optional + or - sign, at most one decimal point (which can be the first character), and at least one digit between 0 and 9. The function should return a boolean value of true if the number entered is a real number, otherwise it should return a boolean value of false. Write a main function to test it out.

(Numerical) Write a program that tests the effectiveness of the rand() library function. Start by initializing 10 counters to 0, and then generate a large number of pseudorandom integers between 0 and 9. Each time a 0 occurs, increment the variable you have designated as the zero counter; when a 1 occurs, increment the counter variable that’s keeping count of the 1s that occur; and so on. Finally, display the number of 0s, 1s, 2s, and so on that occurred and the percentage of the time they occurred.

Mark the following statements as true or false: a. To use a predefined function in a program, you need to know only the name of the function and how to use it. (1) b. A value-returning function returns only one value. (2, 3) c. Parameters allow you to use different values each time the function is called. (2, 7, 9) d. When a return statement executes in a user-defined function, the function immediately exits. (3, 4) e. A value-returning function returns only integer values. (4) f. A variable name cannot be passed to a value parameter. (3, 6) g. If a C++ function does not use parameters, parentheses around the empty parameter list are still required. (2, 3, 6) h. In C + + , the names of the corresponding formal and actual parameters must be the same. (3, 4, 6) i. A function that changes the value of a reference parameter also changes the value of the actual parameter. (7) j. Whenever the value of a reference parameter changes, the value of the actual parameter changes. (7) k. In C++, function definitions can be nested; that is, the definition of one function can be enclosed in the body of another function. (9) l. Using global variables in a program is a better programming style than using local variables, because extra variables can be avoided. (10) m. In a program, global constants are as dangerous as global variables. (10) n. The memory for a static variable remains allocated between function calls. (11)

(Numerical) Heron’s formula for the area, A, of a triangle with sides of length a, b, and c is A=s(sa)(sb)(sc) where s=(a+b+c)2 Write, test, and execute a function that accepts the values of a, b, and c as parameters from a calling function, and then calculates the values of sand[s(sa)(sb)(sc)]. If this quantity is positive, the function calculates A. If the quantity is negative, a, b, and c do not form a triangle, and the function should set A=1. The value of A should be returned by the function.