HELP!! no match for `_IO_ostream_withassign & >> char[36

azucarmom · 03-09-2005, 12:32 PM

I'm trying to write a very basic, quick little program for my C++ class and I'm running into error after error. Seems like I fix one, and another occurs. I'm not even into the meat of the program yet! ah!
Anyway, here is the code:

//P3

#include <string>
#include "files.h"

using namespace std;

int main(void)
{

const int ROW_MAX = 15;
const int COL_MAX = 2;

ifstream fin;
ofstream fout;

int r;
int c;

string ListArray[ROW_MAX][COL_MAX];

ListArray list;

GetInputFile(fin);

while (!fin) //Read the input file
{
for (r=0; r<ROW_MAX; r++)
{
for (c=0; c<COL_MAX; c++)
{
fin >> list[r][c];
}
}
}

// test to check string input
for (r=0; r<ROW_MAX; r++)
{
for (c=0; c<COL_MAX; c++)
{
cout << list[r][c];
}
}
return 0;
}

And here is the contents of files.h, supplied by my professor:
// files.h

#ifndef _FILES
#define _FILES

#include <iostream.h>
#include <fstream.h>
#include <iomanip.h>

using namespace std;

void GetInputFile(/* out */ ifstream& inFile);
// Sets up an input file stream
// Pre: None
// Post: inFile parameter has been opened to the input file specified by the user

void GetOutputFile(/* out */ ofstream& outFile);
// Sets up an output file stream
// Pre: None
// Post: outFile parameter has been opened to the output file specified by the user

#endif

I get the following error when attempting to compile and link:

131p3.cpp: In function `int main()':
131p3.cpp:39: no match for `_IO_ostream_withassign & >> char[36]'

Can someone please tell me what I'm doing wrong? I'm sure it's something insanely obvious and stupid, and I'm so fried I can't figure it out. Spring break my butt!
Thanks!

beforemath · 03-09-2005, 01:32 PM

Just a small question:

Why exactly are you declaring

Code:

string ListArray[Row_Max][Col_Max];

ListArray list;
.
.
.
cout << list[r][c];

instead of using

Code:

string ListArray[Row_Max][Col_Max];
.
.
.
cout << ListArray[r][c];

I'm kind of unclear what the "ListArray list" declaration is for.

Does the code work if you take that out and replace the instances of "list" with "ListArray"?

~bm

azucarmom · 03-09-2005, 01:40 PM

Oops, that should actually be a typedef:

typedef string ListArray[Row_Max][Col_Max];

ListArray list;

And that doesn't fix it, I just get a new error:

/tmp/ccu9baEd.o: In function `main':
/tmp/ccu9baEd.o(.text+0xfc): undefined reference to `GetInputFile(ifstream &)'
collect2: ld returned 1 exit status

Not sure what those mean, any ideas?
Thanks!

azucarmom · 03-09-2005, 03:37 PM

I did figure it out, to make a long story short, I wasn't linking some files correctly and that's what that error was regarding.

Anyway, I've gotten a bit further and I'm trying to compare the name a user types in to the name in my array. Here's the code segment:******************************

cout << "Please enter your name exactly as it appears on the shareholder list." << endl;
cout << "Or, you may type Q to quit." << endl;

cin >> fname;
if ((fname[0]="q")&&(fname[1]=" ")&&(fname[2]=" "))
{
return 0;
}
cin >> lname;
cin.ignore(256, '\n');

for (r=0; r<ROW_MAX; r++)
{
if ( strcmp( fname, list[r]) == 0 )
{

for (c=0; c<COL_MAX; c++)
{ if ( strcmp( lname, list[c]) == 0 )
cout << fname << " " << lname << " may attend";
else
cout << fname << " " << lname << " may NOT attend";
}
}
else
cout << fname << " " << lname << " may NOT attend";
}
**********************************************************************
Now, when I attempt to compile, I get:

131p3.cpp: In function `int main()':
131p3.cpp:54: warning: assignment to `char' from `char *' lacks a cast
131p3.cpp:54: warning: assignment to `char' from `char *' lacks a cast
131p3.cpp:54: warning: assignment to `char' from `char *' lacks a cast
131p3.cpp:65: cannot convert `fname' from type `string' to type `const char *'
131p3.cpp:69: cannot convert `lname' from type `string' to type `const char *'

<sigh> Seems yet again, I've done something wrong - looks to be in my comparision of the strings. How can I fix this?

Thanks everyone!

beforemath · 03-09-2005, 05:03 PM

What is the declaration of fname and lname?

are they:

Code:

string lname[SIZE];

or

Code:

string lname;

If you declared it as the latter, you can't compare

Code:

lname[x] == " "; // you are comparing a char (in theory) with a string

lname[x] == ' '; // you are now comparing char with char
                         // and use == instead of =
                         // you are trying to compare, not trying to assign

and later...
you can't assign fname (a string I'm assuming) to a pointer to a string.
You should probably assign fname = list[x][y] or something.

That looks like what the problem is to me.
hope it helps or sets you in the right direction.

~bm

azucarmom · 03-09-2005, 05:29 PM

they're
string fname, lname;

I need the user to enter his name, which I need to store
(currently cin >> fname>>lname

then, I need to search an array and see if that name is in the array. THe array is 2 columns, 15 rows.
The first column is the first name, the second column is the last.

How do I compare them? Do I have to go char by char in the strings (ugh)?

Thanks!

beforemath · 03-10-2005, 08:42 AM

Nah, you don't have to go char by char.

Some versions of C compiler overload the == operator so you can compare

Code:

if (string1 == string2)
     { 
     do code
     }

but the standard is (or was) that the C compiler doesn't support this operation. Instead (since I see that you have string.h declared up there), you can use strcmp().

Code:

int x;
x = strcmp(string1, string2);
if (x < 0)
     string1 is 'less than' string2
if (x == 0)
     string1 is 'equal to' string2
if (x > 0)
     string1 is 'greater than' string2

remember that your 'list ' variable is a two-dimensional array of strings, so list[r] compared with fname won't work.

list[r][c] compared with fname will work, though.

Let me know if this helps.

~bm

azucarmom · 03-10-2005, 11:47 AM

I got it to work using:

Code:

bool canAttend = false;
for (r=0; r<ROW_MAX; r++)
{
    if (fname == list[r][0] && lname == list[r][1])
   {
     canAttend = true;
     break;
   }
}

if (canAttend)
  cout << fname << " " << lname << " may attend";
else
  cout << fname << " " << lname << " may NOTattend";

I tried strcmp but it didn't work.
I don't know why I was trying to reference list as a one dimensional array! Total brain fart I think.
Thanks for your help.