could you help with me C code?thanks,a little urgent.

Quote:

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Originally Posted by matsp

Right, so the comment that "you already have one loop" is incorrect. It is commented out using #if 0, so there is only one loop. I personally prefer the variant with the while(1) loop.

Aside from STILL not using the value returned by fread, you are also still assuming that the entire file will fit in 1024 bytes, as t is the length of the file, and if we pick an arbitrary file in the system, it may be larger than 1024 bytes. What I'm saying here is that "t" is not the right value to pass to fread.

Further, after you seek to the end of the file, how much data do you expect to be able to read after that? Do you think it may be a good idea to do something about that?

There is a reasion I'm not telling you exactly what to do: You need to learn to UNDERSTAND what your code is doing, not just randomly change it without understanding why. Otherwise, you will never learn how to write programs.

--
Mats

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really appreciate your advise, i know the codes has many bugs and if we choose a random file, it will breakdown.
it is hard for me to do that, though i know much should be done for the program.

at the moment, i just want to make a exercise assign for that question. further work will be done later.the codes will be assessed tomorrow.
hth

My point is that you NEED to understand how your code works, and what affects what.

You can not fix your code without understanding what it does.

You seem to not understand the simple statement of: you need to use the return value from fread. I have yet to see any effort in fixing this part of the problem.

--
Mats

Quote:

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Originally Posted by Adak

I liked the while(1) loop better, myself, but I saw the for loop there, and thought his idea should be followed. HH, if you have no preferences, why not remove the for loop, and put the while(1) loop into it's place.

Note that the if 0 line of code, is gone, and should stay gone.

We do have a problem with the fread() line. IMO "t" should not be in that line. You have a buffer to put the data into, and the data has to fit into that buffer. T has nothing to do with that.

I suspect that T is not even needed, but Matsp is the expert.

I see it as "You're going to take a bunch of apples & put them in a box of 1024, and stack them in a warehouse". You don't care how many apples there are in the truck, because you have to take them all, anyway."

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yes,that metaphor is really good for the question.

i can understand what you are saying.

Matsp is expert, but i am unable follow his guidelines.

i don't know how to do that.

right now, i just want to finish that assign.

perfect programming is a long way for me

Quote:

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Originally Posted by matsp

My point is that you NEED to understand how your code works, and what affects what.

You can not fix your code without understanding what it does.

You seem to not understand the simple statement of: you need to use the return value from fread. I have yet to see any effort in fixing this part of the problem.

--
Mats

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i use getchar() to end the program instead of "return 0", if user enter any key on the keyboard.
does is work?

Quote:

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Originally Posted by hth373737

yes,that metaphor is really good for the question.

i can understand what you are saying.

Matsp is expert, but i am unable follow his guidelines.

i don't know how to do that.

right now, i just want to finish that assign.

perfect programming is a long way for me

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Right, there is a principe called "KISS" - Keep It Simple, Stupid.

You need to make the simplest possible solution to your problem. The while(1) loop looks good, aside from some minor details.

Do you understand the concept of return values from functions AT all?

--
Mats

Quote:

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Originally Posted by hth373737

i use getchar() to end the program instead of "return 0", if user enter any key on the keyboard.
does is work?

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No, that's not at all got anything to do with what I'm talking about.

You are panicing over your current situation looking for a quick fix. If you have only a few hours to finish this, then perhaps you are bound to be late for this assignment. You need to understand what you are doing, and the above makes it perfectly clear that you do NOT understand functions and return values.

--
Mats

Quote:

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Originally Posted by hth373737

i use getchar() to end the program instead of "return 0", if user enter any key on the keyboard.
does is work?

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getchar() should just hold the console window open so you can see the program's output. Hitting Enter key will close it. Not any key, it must be the Enter key.

You still need "return 0" at the end of your main() function. Any function that returns a value, should have a return N at the end, where N is either a number (zero is normal return usually, and anything else is either a special value, or an error). N could also be a variable's value, like "return cash", could return the variable "cash".

Hth, from what I've seen, you will need to REALLY dig into these programming lessons and assignments, and work hard, if you expect to complete them.

Get INTO the real understanding of the basics of the C language and programming. Your education so far, has seemed to skip some basics that you'll need VERY badly, very soon.

Quote:

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Originally Posted by Adak

getchar() should just hold the console window open so you can see the program's output. Hitting Enter key will close it. Not any key, must be the Enter key.

You still need "return 0" at the end of your main() function. Any function that returns a value, should have a return N at the end, where N is either a number (zero is normal return usually, and anything else is either a special value, or an error). N could also be a variable's value, like "return cash", could return the variable "cash".

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thanks for your explanation.

then what should i do with that loop

Quote:

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Originally Posted by matsp

No, that's not at all got anything to do with what I'm talking about.

You are panicing over your current situation looking for a quick fix. If you have only a few hours to finish this, then perhaps you are bound to be late for this assignment. You need to understand what you are doing, and the above makes it perfectly clear that you do NOT understand functions and return values.

--
Mats

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yes...i am in panic with the limit of time.
what can i do with that loop?

Code:

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#include<stdio.h>
#include<string.h>      // for strlen() function.
#include<stdlib.h>      // for exit() function.



int main() 
{ 
        int data[1024];
        char  sourcename[20]; 
        char  destinationname[20];    // redeclaration?
        FILE  *sFile,*dFile; 
        long t;
       
        printf("please input source filename");
 gets(sourcename);
        printf("please input destination filename");
 gets(destinationname);          //sth wrong with it?
       
       
       
 if((sFile=fopen(sourcename,"rb"))==NULL) 
 { 
  printf("fail to open source file\n"); 
  exit(0); 
 }
       
       
 
 if((dFile=fopen(destinationname,"wb"))==NULL) 
 { 
  printf("fail to open destination file\n"); 
  exit(0); 
 } 
       
       
       
       
        fseek(sFile,0L,SEEK_END);
        t=ftell(sFile);  //get the size of the file.
       
       
       
       
                              // the codes below is tough to me
        for(;(feof(sFile)!=0);)
          {
                fread(data,t,1,sFile);
                printf("%s",sFile);
        fwrite(data,t,1,dFile);
                printf("%s",dFile);
            }


       
          fclose(sFile); 
          fclose(dFile);
        return 0;
 
}

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There is nothing wrong with that loop (the loop construct itself - the contents in the loop is still not right, which has to do with the use of "t" and the return value from fread()).

--
Mats

>> yes...i am in panic with the limit of time.

Unfortunately, this is the reality of being unprepared. You don't contend in the motorcross if you don't know how to drive, do you? What makes you think that programming is any different?

Quote:

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Originally Posted by Sebastiani

>> yes...i am in panic with the limit of time.

Unfortunately, this is the reality of being unprepared. You don't contend in the motorcross if you don't know how to drive, do you? What makes you think that programming is any different?

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every second counts.

i have just finish one essay and one report and then rush into this C programming.

the assign will be handin within about 30 hours day to night.

i got stuck with it

Quote:

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Originally Posted by matsp

There is nothing wrong with that loop (the loop construct itself - the contents in the loop is still not right, which has to do with the use of "t" and the return value from fread()).

--
Mats

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sorry , i don't understand what to do

Code:

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int foo(void)
{
  return 7;
}


int main()
{
    int x;
    x = foo();
    printf("x = %\n", x);
    return 0;
}

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Here is an example of a function returning a value, and we use this value to print it. fread ALSO returns a value, which is "how many data elements was read". You need to use that value to give to fwrite to make sure that if you only have "half a crate of apples", fwrite doesn't think it's a full crate.

--
Mats

>> i have just finish one essay and one report and then rush into this C programming.

Right, but you *know* what you were getting into, so why not learn as much as possible *before* jumping into a program this complicated? Read some books. Practice writing a few simple programs. Approach each task individually, eg: working with different data types, handling user input/output, reading/writing files, etc. You may get a zero on this assignment, but if you work hard, you'll do much better on future ones.