segmentation fault

[freddyjones39]

I am a beginner (very much so) in computer programming, I use a gcc compiler.
The following program is not yet finished, but is at a stage that it should atleast run. It compiles fine, and asks for, and execpts value "b", but then geves a segmentation error message, and I have no idea why. Any help would be appretiated.

#include<iostream>
#include<iomanip>
using namespace std;
 
double get_input (char note[], double min);
//Requires: A name of the item.
//Promises: "a" (a weight to length ratio).
 
double calc_a (double b, double l, double g);
//Requires: Previously calculated "a".
//Promises: Total a of cable.
 
int main()
{
  cout<<"main"<<endl;
  double b=get_input("b",0);
 
  double l=get_input("l",2*b);
 
  double g=get_input("g",0);
 
  double a=calc_a(b,l,g);
  cout<<"a is_"<<a<<endl;
}
 
double get_input (char note[],double min)
{
  cout<<"input "<<note<<endl;
  cin>>note;
  return 1;
}
double calc_a (double b, double l, double g)
{
  double a = get_input("g",0);
  while ((l*a-g*(pow(1+a,b)-1))!=0)
    {
      a=(a-(l*a-g*(pow(1+a,b)-a)))/(l-g*b*(pow(b+1,b-1)));
    }
  return a;
}

[sicarie]

You do know that you are trying to use a function that you haven't defined yet, right? I'm referring to pow(), when you haven't included the cmath library?

Hmm, so I haven't seen get_input() before (or if I has, it was a very long time ago), why not just use cin?

[freddyjones39]

Thanks for the speedy reply. I think I got it figured out.

[freddyjones39]

I'm just trying to learn how to use functions.

[sicarie]

Thanks for the speedy reply. I think I got it figured out.

Awesome, care to post what you figured out, just in case someone else has the same issue?

[freddyjones39]

I re-wrote it completely, and the only thing that I can see that is different is the boolean expression after the while statement, and also my calc_a formula was wrong.