Getting frustrated

**kippwinger** · 07-02-2003

Hey, I am trying to read in data into 3 parallel arrays to manipulate later. When I test to see what is in each on after reading them in it is really messed up.

Here is my code:

Code:

#include <iostream.h>
#include <fstream.h>
#include <iomanip.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>

//Global Variables
ifstream infile;
ofstream outfile;

typedef char string[30];

//Prototypes

int main()
{
string social[30],phone[30],name[30];
int i;
	infile.open("In599A.Dat");
		while(!infile.eof())
		{
			for(i=0;i<23;i++)
			{
			infile>>social[i]>>phone[i];
			infile.getline(name[i],30,'\0');
			

			}
		}
		for(int j=0;j<22;j++)
			cout << social[j] << endl;


	return 0;
}

Here is the contents of the file I am reading from:

Code:

526334512 2665312 Jones, Julie Claire
264910093 2689022 Morgan, James Walter
587194309 5441234 Allen, Mary Ann
264881234 2669128 Thompson, William C
267456543 2683139 Williamson, Terry H
587521937 2680145 Robertson, Susan Leigh
588552584 2661357 Yelverton, Ted W
267552894 2664422 Bolton, Rebecca Lynn
576885197 5451992 Edwards, Tracy Ann
234675891 2610094 Walker, LaTonya B
641225537 2664949 Young, Henry Clarke
247569311 2665278 Thompkins, Marcia R
455124690 2681189 Price, Adam Paul
426133299 2684518 Vickery, Kathy Ann
587023057 2685572 McPhail, Ann K
258199876 5446993 Clark, Rodney P
256451389 5441898 Robbins, Terry Lynn
456113278 5453358 Hickman, Susan Leigh
257126677 2668818 Upton, Richard P
487931470 2665001 Shaw, Anna Jane
289889637 2665017 Zachary, Phillip F
587366338 2610358 Calhoun, Roderick T

thanks.

**knave** · 07-02-2003

I thought you were supposed to keep peoples social security numbers private?

**kippwinger** · 07-02-2003

they're fake numbers

**Zach L.** · 07-02-2003

>> I thought you were supposed to keep peoples social security numbers private?

Doubt those are real SSNs.

Anyways, I think your problem is in getline. Lines in a file do not end in \0. In fact, I believe you can leave the delimiter out of the function call.

**kippwinger** · 07-02-2003

Bam! that was it. I have a few more questions to ask. I will continue to ask them in this forum when they arise. Thanks again.

**kippwinger** · 07-02-2003

Okay, I need to sort the name array in alphabetical order, but I need to keep the other arrays to correspond with the moves that I do. I tried to start by using the Bubble Sort and my program keeps crashing.

Please take a look at my code and tell me what might be the problem:

Code:

I did a typedef char string[30] as a global variable..


void bubblesort(string name[], int size)
{
	int i, j;
	string temp;
	for(i=0;i<size-1;i++)
		for(j=1;j<size;j++)
			if(strcmp(name[j],name[j-1])<0)
			{strcpy(temp,name[j]);
			strcpy(name[j],name[j-1]);
			strcpy(name[j-1],temp);
			}
}

**quzah** · 07-02-2003

typedef char string[30];

I'll never understand why people find the need to do this. That being said, you really shouldn't call you "string" string. After all, there is already a class called string (#include <string>), and anything starting with 'str' is a reserved key word.

Furthermore, why don't you just use a structure to store all of your items, and have an array of those?

[edit] Actually, since you're including <string.h>, I'm surprised this even compiles. [/edit]

Quzah.

**kippwinger** · 07-02-2003

We haven't studied structs yet. I hear they are a lot easier to use. For now, I will stick with what I know.

**Zach L.** · 07-02-2003

<string.h> is still a valid header in C++, equivalent to <cstring> essentially.

Anyways, Quzah's structure idea is the way to go. Store your data in the structure, provide a suitable operator< for it, keep a vector, and use the standard sort algorithm.

**confuted** · 07-02-2003

Why don't you use the string class instead of the char array to store the strings? I just checked it out today, and it's loads easier. Here's a link with a good section on the STL string class and a little on a couple other STL classes.

http://www.msoe.edu/eecs/cese/resources/stl/

**quzah** · 07-02-2003

Originally posted by Zach L.
<string.h> is still a valid header in C++, equivalent to <cstring> essentially.

Yeah, I was thinking that the 'string' class was defined in said header.

Quzah.

**kippwinger** · 07-02-2003

thanks for your help, but my teacher is really picky about us moving ahead. She wants us to understand how to operate with parallel arrays.

**quzah** · 07-02-2003

You should write a function to swap strings. Something like:

Code:

void swapstuff( string array[], size_t fromhere, size_t tohere )
{
    buffer

    copy tohere to buffer
    copy fromhere to tohere
    copy buffer to fromhere
}

The hint here is that you use the 'cell' number to swap that location in your array. You'd call it with something like:

swapstuff( array1, 5, 2 );
swapstuff( array2, 5, 2 );
swapstuff( array3, 5, 2 );

This way, you end up swapping all three arrays, keeping their values matching.

I'll leave the actual copy process to you. It should be trivial.

Note: I used "string" as your typedef, though I'd really suggest changing it.

Quzah.

**kippwinger** · 07-02-2003

I think you've lost me...

**Zach L.** · 07-02-2003

He's saying this:

Write a function to swap two values in an array. This function should take the array as an argument, as well as the indices to swap. Then, simply call that swap function on all your arrays each time you swap something in the sort. That way, all arrays stay synchronized.

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