Solved

fstream problem

Posted on 2003-11-28
9
332 Views
Last Modified: 2010-05-18
hallo,
new to c++,i have written a code to write a data ,

  FILE *file;
  file = fopen(fileName,"r");
  ofstream wfile(writefileName);
   
  wfile << "#VRML V2.0 utf8"<<endl;
  wfile << "#Wilson"<<endl;
   
   d = 0;
   while ((str = fgets(line,LINESIZE,file)) && !feof(file))
      {
      if (!strcmp(token,"v")) {

        wfile << "#" << endl;
      cout<<"wfile write ... "<<endl;
      ...........
               }
        }


but after it works,there r only
#VRML V2.0 utf8
#Wilson
in this data

what's happened?
and how can i solve it?

thanks

regards
wilson
0
Comment
Question by:iux
  • 3
  • 2
  • 2
  • +2
9 Comments
 
LVL 86

Accepted Solution

by:
jkr earned 500 total points
ID: 9841237
>>what's happened?

You are not verifying that the input file was opened successfully:

file = fopen(fileName,"r");

if (!file) {

  cout << "FAILED to open " << fileName << endl;
}

So, it might just be that the file could not be found.

0
 
LVL 86

Expert Comment

by:jkr
ID: 9841241
btw, it is in general not a good idea to mix C style IO with C++ - why not using an 'ifstream' for the input?
0
 

Author Comment

by:iux
ID: 9841271
i have written
if (!strcmp(token,"v")) {
    cout<<"v read..."
    ....
it works,so i think it opens seccessfully

and i found with sscanf and fscanf much easier than get() and getline for input and ofstream << for output(code easier han fwrite)

its really the problem cause mix?

regards
wilson
0
Is Your AD Toolbox Looking More Like a Toybox?

Managing Active Directory can get complicated.  Often, the native tools for managing AD are just not up to the task.  The largest Active Directory installations in the world have relied on one tool to manage their day-to-day administration tasks: Hyena. Start your trial today.

 
LVL 1

Expert Comment

by:d_iego
ID: 9841347
maybe if you put str= fgets(line,LINESIZE,file) outside the while condition
0
 

Author Comment

by:iux
ID: 9841551
thx,but i think its necessary for this code
0
 
LVL 6

Expert Comment

by:GloomyFriar
ID: 9842197
>    if (!strcmp(token,"v")) {
Why "token"? May be "str"?

0
 
LVL 6

Expert Comment

by:GloomyFriar
ID: 9842214
And keep in mind that the strcmp() does case-dependent comparison.
It mean that the "#" will be written to out-file when you read exactly "v" from in-file only.
0
 

Author Comment

by:iux
ID: 9842491
i have defined before
char token[1000];


and i have written
if (!strcmp(token,"v")) {
    cout<<"v read..."

it works when compiler
so i thinks it has read "v" successfully
0
 
LVL 1

Expert Comment

by:travd
ID: 9872346
Does the:

cout<<"wfile write ... "<<endl;

output show up on stdout?
0

Featured Post

ScreenConnect 6.0 Free Trial

Want empowering updates? You're in the right place! Discover new features in ScreenConnect 6.0, based on partner feedback, to keep you business operating smoothly and optimally (the way it should be). Explore all of the extras and enhancements for yourself!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article shows you how to optimize memory allocations in C++ using placement new. Applicable especially to usecases dealing with creation of large number of objects. A brief on problem: Lets take example problem for simplicity: - I have a G…
Basic understanding on "OO- Object Orientation" is needed for designing a logical solution to solve a problem. Basic OOAD is a prerequisite for a coder to ensure that they follow the basic design of OO. This would help developers to understand the b…
The goal of the video will be to teach the user the concept of local variables and scope. An example of a locally defined variable will be given as well as an explanation of what scope is in C++. The local variable and concept of scope will be relat…
The goal of the video will be to teach the user the difference and consequence of passing data by value vs passing data by reference in C++. An example of passing data by value as well as an example of passing data by reference will be be given. Bot…

809 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question