C++ Progression

Oct 10, 2012 at 5:40pm

#include <iostream>
using namespace std;
int main ()

{
    double d;
    double startnum;
    double n;

    cout <<"Starting number - " << endl; 
    cin >> startnum;

    cout <<"D - "<< endl;cout << endl;
    cin >> d; cout << endl;

    cout <<"N - "<< endl;cout << endl;
    cin >> n; cout << endl;

    for(double x = startnum, d = d; x<=n ; x++, d++)
    {
       cout << x << endl;
    }

    return 0;
}

Edit & run on cpp.sh

Lets say I enter start number(startnum=2), d (d=2), n (n=5).
After i chosen the numbers i want the output to look like this.

4
6
8
10
12

At this moment i'm only getting

4 first number
5 |
6 |No d
7 |is added.
8 |

"d" is not being added after the first number.

Thanks in advance.

EDIT:

for(double x = startnum; x<=n; x++)
    {
       cout << x << endl;
    }

if the starting number is 66 , d is 2 and n is 4, it doesn't even output anything. I've no idea what am i doing wrong.

Last edited on Oct 10, 2012 at 5:54pm

Oct 10, 2012 at 5:53pm

codewalker (394)

Looking at the program the output should be
3
4
5
6
for the given input

For what you need to achieve

#include <iostream>
using namespace std;
int main ()

{
  double d;
  double startnum;
  int n;

  cout <<"Starting number - " << endl;
  cin >> startnum;

  cout <<"D - "<< endl;cout << endl;
  cin >> d; cout << endl;

  cout <<"N - "<< endl;cout << endl;
  cin >> n; cout << endl;

  for(int x = 0; x < n ; x++)
    {
      cout << (startnum += d) << endl;
    }

  return 0;
}

Edit & run on cpp.sh

Oct 10, 2012 at 5:53pm

closed account (3qX21hU5)

Im not really getting what you are trying to do. What is the exercise question? Im still also very new to programming so I might be missing something but could use alittle more info.

Oct 10, 2012 at 5:53pm

ResidentBiscuit (4459)

You do some weird things. No need for the semi colons to add more endl's. Can just keep inserting them into the stream. Not sure why you're using doubles? And your for loop is strange. Why do you have d involved in the loop at all? It doesn't do anything but just add 1 to itself. All your program does is print startum through n, one at a time.

Oct 10, 2012 at 6:00pm

DontSeeMinusMinus (16)

Excuse me for not being more specific.
Basically, i have to make geometric progression program where the user enters all the numbers, starting number, the length of progression, etc.

@codewalker (49) Thanks!

Last edited on Oct 10, 2012 at 6:02pm

Oct 10, 2012 at 7:28pm

DontSeeMinusMinus (16)

Oh, and one quick question.
Can I somehow make an error saying that data which i entered was wrong?
For example.
I enter characters instead of numbers.

Oct 10, 2012 at 7:43pm

closed account (3qX21hU5)

http://www.cplusplus.com/reference/iostream/cerr/

that should help alittle

Oct 10, 2012 at 10:36pm

DontSeeMinusMinus (16)


#include <iostream>
using namespace std;
int main ()

{
    double q; 
    double startnum; 
    int ok; 

    do
    {

    cout <<"First number - " << endl; cout << endl;
    cin >> startnum; cout << endl;

    cout <<"Q - "<< endl; cout << endl;
    cin >> q; cout << endl;

    cout <<"First (5) numbers - "<< endl; cout << endl;
    for(int x = 0; x < 5 ; x++) 
    {

      cout << (startnum += q) << endl;

    }

    cout << endl;
    cout << " Continue  (1) End (0)?" << endl; 
    cin >> ok;
     } while (ok == 1);

    return 0;
}

Edit & run on cpp.sh

Could anyone by any chance help me to write
if/while error for both cin >>.
Basically, if user enters non-number there should be a "Wrong number!"
And then it jumps to cout << " Continue (1) End (0)?" << endl; part.

Again, appreciate the help.

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