Problem with reading in a word

[MariyaGel]

I have wrote the program and it worked fine until I had to include one more array into it. As you can see below the two arrays of volume and mass are working properly now I need to include a third array which reads in the sample name that coincides with the mass and the volume. I have tried the getline function and that didnt work. This is my first class in computer programming and im very new to it so if i have made obviouse mistakes i apologize. I tried as much as i can myself and Im not exactly sure how to proceed. Please help

Here is the program:

# include <string>
# include <iostream>
# include <fstream>
using namespace std;
void readinput (double[], double[], string, int, ifstream &infile);
void printvalues (double[], double[], string, int, ofstream &outfile);
void linearsort (double[], double[], string, int);
void bubblesort (double[], double[], string, int);
int line_search (double[], double, int);
int main()
{
    ofstream outfile ("prog7.txt");
    ifstream infile ("assignment7.txt");
    int n, position;
    if (infile.bad())
    {
       cout<<"unable to read from file";
       exit(1);
    }
    infile>>n;
    double mass[n], volume[n], newnumber; 
    string name;  
    readinput(mass, volume, name, n, infile);
    cout<<name[0]<<name[1]<<name[2]<<name[3]<<name[4]<<name[5];
    printvalues(mass, volume, name, n, outfile);
    linearsort(mass, volume, name, n);
    printvalues(mass, volume, name, n, outfile);
    bubblesort(volume, mass, name, n);
    printvalues(mass, volume, name, n, outfile);     
    while(infile>>newnumber)
    {
          position=line_search(mass, newnumber, n);
          if (position == -1)
          {
              cout<<"The number "<<newnumber
                  <<" does not occure in the mass array"<<endl;  
          }
          else
          {
              cout<<newnumber<<" is found at position "<<position
                  <<". The volume of that sample is "<<volume[position]<<endl;
          }
          position=line_search(volume, newnumber, n);
          if (position == -1)
          {
              cout<<"The number "<<newnumber
                  <<" does not occure in the volume array"<<endl;
          }
          else
          {
              cout<<newnumber<<" is found at position "<<position
                  <<". The mass of that sample is "<<mass[position]<<endl;
          }
          cout<<endl;
    }       
    infile.close();
    outfile.close();
    getchar();
    return 0; 
}
 
 
//Function readinput:
//Input: 2 arrays, int n, and infile
//Process: Read the data values from the input values into 2 arrays.
void readinput (double a[], double b[], string c[], int n, ifstream &infile)
{
     for (int i=0; i<n; i++)
          infile>>a[i]>>b[i]>>c[i];
     return;
}//read input
 
 
 
//Function bubblesort:
//Input: 2 arrays
//Process: Sorts the arrays in ascending order of volume
void bubblesort (double a[], double b[], string c[], int n)
{
       double temp, temp2;
       string temp3;
       bool swapped;
       do
       {
            swapped = false;
            for (int i=0; i<n-1; i++)
                 if (a[i] > a[i+1])
                 {
                    temp = a[i];
                    temp2 = b[i];
                    temp3 = c[i];
                    a[i] = a[i+1];
                    b[i] = b[i+1];
                    c[i] = c[i+1];
                    a[i+1] = temp;
                    b[i+1] = temp2;
                    c[i+1] = temp3;
                    swapped = true;
                 }
       }
       while (swapped);
       return;
}//bubblesort
 
 
//Function linearsort:
//Input: 2 arrays
//Process: Sorts the arrays in descending order of mass
void linearsort (double a[], double b[], string c[], int n)
{
     double temp, temp2;
     string temp3;
     for (int i=0; i<n-1; i++)
          for (int j=i+1; j<n; j++)
               if (a[i] < a[j])
               {
                  temp = a[i];
                  temp2 = b[i];
                  temp3 = c[i];
                  a[i] = a[j];
                  b[i] = b[j];
                  c[i] = c[j];
                  a[j] = temp;
                  b[j] = temp2;
                  c[j] = temp3;
               }
     return;
}// linearsort
 
 
//Function linsearch:
//Input: double array, number to be searched for and n
//Process: Determines whether or not the input number occurs in the array
//Output: The position of that number or -1 if it cannot be found
int line_search (double a[], double newnumber, int n)
{
    for (int position=0; position<n; position++)
         if (a[position] == newnumber)
             return position;
    return -1;
}//line_search
 
 
//Function printvalues:
//Input: 2 arrays, int n and outfile
//Process: To print the arrays into a table.
void printvalues (double a[], double b[], string c[], int n, ofstream &outfile)
{
     outfile<<"        Collected Data"<<endl;
     outfile<<"Mineral      Mass      Volume"<<endl;
     for (int i=0; i<n; i++)
     {
          outfile.setf(ios_base::fixed, ios_base::floatfield);
          outfile.precision(2);
          outfile.setf(ios::left);
          outfile.width(12);
          outfile<<c[i]<<a[i]<<b[i]<<endl;
     }      
     outfile<<endl<<endl;
     return;
}//printvalues

[Banfa]

I think you problem is that using you syntax

string name;

should be

string name[n];

In fact you have notably left out the array specifiers [] in a lot of places where you are passing the name parameter.

Additionally the code

double mass[n];

doesn't compile for me as standard C++ does not support dynamically sized arrays (not sure which version you are using though).

[MariyaGel]

That was absolutely correct I can't believe I missed that. It worked out perfectly , Im using Dev-C++ and double mass[n] workes with no problem. I just got confused how i was suppose to declare an array of words, I wasnt sure you can have an array or words and not just characters.
Thank you very much

[Banfa]

Im using Dev-C++ and double mass[n] workes with no problem.

That is fine but you had better be sure that your tutor/lecturer is too (assuming you have one.

...

Now on a point of style you have code similar to the following

    temp = a[i];
    temp2 = b[i];
    temp3 = c[i];
    a[i] = a[i+1];
    b[i] = b[i+1];
    c[i] = c[i+1];
    a[i+1] = temp;
    b[i+1] = temp2;
    c[i+1] = temp3;
 

In both of your sort routines. Now this code works (which is why it is a style point and not a logic point) but this is not very elegant, this code logical performs

For array a swop the values located at i and i+1
For array b swop the values located at i and i+1
For array c swop the values located at i and i+1

which you have written long handed. To neaten it you could easily write Swop functions for the 2 types of variable use (double and string) something with the prototypes

void Swop(double &op1, double &op2);
void Swop(string &op1, string &op2);

these functions would probably embody the code you already have (i.e. use a temporary variable) and then the code becomes

    Swop(a[i], a[i+1]);
    Swop(b[i], b[i+1]);
    Swop(c[i], c[i+1]);
 

which looks much better and says what is happening.

If you really wanted to get snazzy rather than write 2 functions you could write a single template function

template <class T>
void Swop(T &op1, T &op2);

but that may be a little bit complex for a beginner.