Computer Science
and Programming
Prof. Gregory Safko
Lab 3
1. Testing an integer (inttest.cpp)
Write a function testInt that accepts one integer
parameter, and returns a character, 'P' if the number is
positive, 'N'
if it is negative, or 'Z'
if it is zero.
The function prototype (above main)
should look like this:
char testInt(int n);
and
the function definition (below main) should look something like this:
char testInt(int n)
{
// The function may have its own "local" variables,
// just like variables in main.
// The code here does stuff... (DON'T use "testInt" as a variable)
return (an expression giving the result) ;
}
return
is allowed more than once within a function. The first return statement
that is executed will exit the function and indicate the return value to be
used.
(Examples: return
'X'; or if
(n < 1) return 'a';)
Also write a suitable main program to demonstrate your function.
2.
Even/odd test with function (evenodd.cpp)
Write
a function that takes a single int parameter and returns a bool
value, true
if the integer passed in is even, false if it is odd.
The
function prototype should look like this:
bool isEven(int n);
Also
write a main program that prompts for a number, and tests that number, the
number plus one, and the number plus two. Your program must make use
of the function you defined.
Here
are two example runs, showing one possible output format:
Please enter an integer: 4
4 is even
5 is odd
6 is even
Press any key to continue
Please enter an integer: 33
33 is odd
34 is even
35 is odd
Press any key to continue
3.
Divisor testing (divisor.cpp)
Write
a program that prompts for an integer n, and indicates whether it is divisible
from to 2 to n/2. (This is an expansion of your divtest.cpp program)
Here
is one possible output format, showing two example runs:
Enter an integer: 18
18 is divisible by 2.
18 is divisible by 3.
18 is not divisible by 4.
18 is not divisible by 5.
18 is divisible by 6.
18 is not divisible by 7.
18 is not divisible by 8.
18 is divisible by 9.
Press any key to continue
Enter an integer: 11
11 is not divisible by 2.
11 is not divisible by 3.
11 is not divisible by 4.
11 is not divisible by 5.
Press any key to continue
Optional this week (will be required later): Notice that the number 11
is a prime number (a number whose only divisors are itself and 1).
Write code to check that if a number n fails divisibility up to n/2,
then it must be a prime number.
4.
Dropping the lowest of 3 grades, and 4 grades (droplow.cpp)
Write
two overloaded functions, both named dropLowest ; one will take
three ints as arguments, and the other will take 4 ints as
arguments. In both cases, each function returns the sum of the largest values
minus the lowest as an int. For example, dropLowest(100,70,90)
should return 190; dropLowest(30,-40,-40)
should return -10; dropLowest(50,20,100,100)
should return 250; and dropLowest(10,10,10,10)
should return 30. (Notice that the order does not matter.)
The
function prototype (above main) should look something like this:
int dropLowest(int a, int b, int c);
int dropLowest(int i, int j, int k, int l);
/*(Recall that the parameters a,b,c,i,j,k,l are optional, and are for
human-readable purposes only) */
HINT:
You can find the sum of all three numbers, then find the smallest of the three
and subtract it from the sum.
Also
write a suitable main program demonstrating your function. You may have it call
your function with an appropriate set of fixed test cases (dropLowest
should work reasonably when some or all of its arguments (values "plugged
in") are equal), or you may have it prompt for numbers from the keyboard
and print the result.