Void functions for c++

[willywonka]

Hi all, I am a first year student at the university of South Africa. I am doing my degree via correspondence, thus no lectures. I am working through the prescribed book as best i can but they still assume a little bit of fore knowledge of programming which i don't have! Please tolerate me for asking what should probably be a very easy question for you all.

They want me to write a void function which does the following. A number is entered, eg 6 ant then the following should be the output;

#^^^^^^^^^#
^#^^^^^^^#^
^^#^^^^^#^^
^^^#^^^#^^^
^^^^#^#^^^^
^^^^^#^^^^^

I know that a 'for' loop is required to do this, but I cant figure out how many to nestle!?

The formula (2 * nrP - 2 * i - 1) is given as a hint where 'nrP' is the number of rows entered by the user for the function to use and 'i'
will be the row generated by the loop. I have no examples of this in my text book to refer to for help.

If someone could just steer me in the right direction it will already be a huge help.

PLEASE HELP!!

thanks

[Salem]

int nrP = 6;
for ( i = 1 ; i < nrP ; i++ ) {
  cout << i << " " << (2 * nrP - 2 * i - 1) << endl;
}

Notice anything about the sequence of numbers?

[jwill113]

First, have you started any code? What parameters are you going to use in your code? Is it a simple iostream or an fstream that's required. Post what you have so far so we can help you out.

[willywonka]

First, have you started any code? What parameters are you going to use in your code? Is it a simple iostream or an fstream that's required. Post what you have so far so we can help you out.

I have started with the problem. This is what i have so far :

// Draws shape V
#include<iostream>
using namespace std;

void drawShape (int nrP)
{
    for (int i = 1; i <= nrP; i++)
    {    for (int j=2; j<=i; j++)
         {cout << "#";
            for(int j=0; j < i; j++)
            cout << "^";  }
          
}

int main ()
{
    int nr;
    
    cout << "Number of rows : ";
    cin >> nr;
    drawShape(nr);
    
    return 0;
}

I just can't figure out where to put the formula provided as a hint, and the loops inside the function have me baffled. I feel a little lost, especially with the last row. how do get just one '#' sign in the last row. does it require a different loop all of its own??? Does the formula make provision for it. I am busy catching up on my calculus also, thus you can see i bit quite a big bit off for myself.

[willywonka]

int nrP = 6;
for ( i = 1 ; i < nrP ; i++ ) {
  cout << i << " " << (2 * nrP - 2 * i - 1) << endl;
}

Notice anything about the sequence of numbers?

I have also tried the following, but it goes into an infinite loop, but I can't see why. I think i am over thinking this problem or I am trying to overcomplicate it. Here's what I tried:

void drawShape (int nrP)
{
    for (int i=1; i <= nrP; i++)
    {    
        for (int j=i-1; j<=i; j++)
         cout << "^";
        for (int k=1; k <=i; k++)
         cout << "#";
        for (int l=(2*nrP-2*i-1); l<=i; l++)
         cout << "^";
         
    cout << endl;
    }
    cout << endl;
}

[Salem]

So do it in stages, say the spaces up to and including the first hash.

You don't have to write the whole thing just to make progress.

[mrnutty]

So do it in stages, say the spaces up to and including the first hash.

You don't have to write the whole thing just to make progress.

Exactly the idea behind " Divide and conquer " strategy, which
in fact is very intuitive.

[willywonka]

Thanks for all the help guys. I got it in the end. Here is my program, tell me if this is similar as to what you would have done;

// Draws shape V
#include<iostream>
using namespace std;

void drawShape (int nrP)
{
    for (int i=1; i <= nrP-1; i++)
    {   
        int x,y;
        x=i-1;
        y=2*nrP-2*i-1;

        for (int j=1; j<=x; j++)
         cout << "^";
        for (int j=1; j<=1; j++)
         cout << "#";
        for (int j=1; j<=y; j++)
         cout << "^";
        for (int j=1; j<=1; j++)
         cout << "#"; 
        for (int j=1; j<=x; j++)
         cout << "^";         

         cout << endl;
    }
    // Last row
        for (int j=1; j<=nrP-1; j++)
         cout << "^";
        for (int j=1; j<=1; j++)
         cout << "#";
        for (int j=1; j<=nrP-1; j++)
         cout << "^";
    cout << endl;
} 


int main ()
{
    int nr;

    cout << "Number of rows : ";
    cin >> nr;
    cout << endl;
    drawShape(nr);
    cout << endl;

    return 0;
}