[help]C++, Discount calculation

For class I am supposed to write a program to calcualte discounts...

Using a "for" loop have the program calculate the actual perchase price after ther discount for the nest $20 in $0.50 increments...

Example

Starting Price:
Percent discount:

Price	 -Diss	New $
$1.00	 $0.20 $0.80
$1.50	 $0.30 $1.20
$1.00	 $0.40 $1.60
........
$21.00 $4.20 $16.80

Now here is my code... I am useing VS.NET 2005 Beta 1 and in wont let me compile with "std::" infront of the i/o streams... Why do I need them?

 #include <iostream>
int main() {
// Variables
float startprice;
float discount;
float h;

// info
std::cout << "Enter the Starting Price: t$"; 
std::cin >> startprice;	 
std::cout << "Percent Discount: t"; 
std::cin >> discount;

//For loops and stuff
for(h = startprice; h <= (20 + startprice); (h+.5)) { 
std::cout << "Pricet-DisctNew $";
std::cout << h << "t" << h/discount << "t" << h-(h / discount); 
}
return 0;
}

#257117

Try:

#include <iostream>

using namespace std;

'

// ...

BTW, you will need an std::endl somewhere to flush the cout-buffer to the screen actually.

#257118

Try:

#include <iostream>
using namespace std;
'
// ...

BTW, you will need an std::endl somewhere to flush the cout-buffer to the screen actually.

Yeah, try what he said, but take out all the std::'s in front of your couts and cins after you put the using namespace in there.

Also, std::endl will actually force a hard-return into your stream. If you want the input right beside your prompts, you could probably use put an std::flush on the end, if I'm not mistaken.

#257164

Okay, I did all that and I get mostly the right answers... but...

I don't understand why I get this where the $1 should be evcery thing else works

Enter the Starting Price:	   $1
Percent Discount (in %):		20
Price		   -Disc		   New $
$1			  $-1.07374e+008		  $1.07374e+008
$1.5			$0.3			$1.2
$2			  $0.4			$1.6
$2.5			$0.5			$2
$3			  $0.6			$2.4
$3.5			$0.7			$2.8
$4			  $0.8			$3.2
$4.5			$0.9			$3.6
$5			  $1			  $4
$5.5			$1.1			$4.4
$6			  $1.2			$4.8
$6.5			$1.3			$5.2
$7			  $1.4			$5.6
$7.5			$1.5			$6
$8			  $1.6			$6.4
$8.5			$1.7			$6.8
$9			  $1.8			$7.2
$9.5			$1.9			$7.6
$10			 $2			  $8
$10.5		   $2.1			$8.4
$11			 $2.2			$8.8
$11.5		   $2.3			$9.2
$12			 $2.4			$9.6
$12.5		   $2.5			$10
$13			 $2.6			$10.4
$13.5		   $2.7			$10.8
$14			 $2.8			$11.2
$14.5		   $2.9			$11.6
$15			 $3			  $12
$15.5		   $3.1			$12.4
$16			 $3.2			$12.8
$16.5		   $3.3			$13.2
$17			 $3.4			$13.6
$17.5		   $3.5			$14
$18			 $3.6			$14.4
$18.5		   $3.7			$14.8
$19			 $3.8			$15.2
$19.5		   $3.9			$15.6
$20			 $4			  $16
$20.5		   $4.1			$16.4
$21			 $4.2			$16.8

#257199

I don't understand why I get this where the $1 should be evcery thing else works

Don't know why it'd be doing that, but a current code listing might help.

#257357

Code dump

 
#include <iostream.h>
using namespace std;
int main() {
 // Variables
 float startprice;
 float discount;
 float h;
 float j;
 float k;

 // info
 cout << "Enter the Starting Price: t$"; 
 cin >> startprice;	   
 cout << "Percent Discount (in %): t";	
 cin >> discount;

 //For loops and stuff
 cout << "Pricett-DiscttNew $n";
 for(h = startprice; h <= (20 + startprice);h) {
 k = h * j;
 j = discount / 100;

  cout << "$"<< h << "tt" << "$"<< k  << "tt" << "$" << (h - k) << "n";
  h = h + 0.5;
 }
return 0;
}

#257457

When you output the -Disc variable, try typecasting it to an int.

cout << "$"<< h << "tt" << "$"<< [b](int)[/b] k  << "tt" << "$" << (h - k) << "n";

(change marked in bold)

#257473

cout << "$"<< h << "tt" << "$"<< (int) k  << "tt" << "$" << (h - k) << "n";

Should be:

cout << "$"<< h << "tt" << "$"<< static_cast<int>(k)  << "tt" << "$" << (h - k) << "n";

#257486

Actually, the starting value of the variable j is undefined in the first loop iteration. Just declare is as

float j = 0;

and the first result line should be ok

#257491

@ AndreasV: C++ showoff! I got that code out of my old C++ book... guess it's time for a new book

...or just stick to VB.NET

#257499

cin >> discount;



 //For loops and stuff

 cout << "Pricett-DiscttNew $n";

 for(h = startprice; h <= (20 + startprice);h) {

 k = h * j;

 j = discount / 100;

Vorlon was half right. The first time through the loop, you multiply h times j before you even assign j. However, his solution will output wrong results. You should have this:

cin >> discount;



 j = discount / 100;



 //For loops and stuff

 cout << "Pricett-DiscttNew $n";

 for(h = startprice; h <= (20 + startprice);h) {

 k = h * j;

That'll solve your problem.

Oh, and don't typecast to an int. Since prices (and discounts) are in dollars and cents, using floats was the right idea.

#257558