***Also, I'm trying this approach as a resolve for your question. But I thik its a more appropriate approach to be used for this question***
#include <iostream>
using namespace std;
int main()
{
int a,b,c;
double r;
char ch,o,m,p;
c=0;
cout<< "Enter your spending limit."<<endl;
cin>>b;
cout<< "Please choose between Pine, Oak, Mahoganhi."<<endl;
cin>>ch;
switch(ch)
{
case 'p':
a = 100;
do
{
r=c+a;
cout<<r<<endl;
c=r;
}
while(r!=b);
break;
case 'o':
a=225;
do
{
r=c+a;
cout<<r<<endl;
c=r;
}
while(r!=b);
break;
case 'm':
a=350;
do
{
r=c+a;
cout<<r<<endl;
c=r;
}
while(r!=b);
break;
}
return 0;
}