structure equivalant in java
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Torsten suggests a bean which may well be a good answer. However, it is difficult to suggest a better alternative without knowing some more about what you are trying to achieve.
Just say 'NO' to evaluated arguments for diadic functions! Ash
Actually I have I programme which write in file with some fixed header in files . which is in form of structure like struct _somename { int somenuml; int somenum2; int somenum3; char databuffer1[100]; // very long struct }; // initialize struct struct _somename mystruct; mystruct.somename = 1; //------ // ans finaly open some file and write to file fwrite(&mystruct,1,sizeof(struct _somename)); Now I want to convert same c programme in java due to some technical reason
Trioum
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Actually I have I programme which write in file with some fixed header in files . which is in form of structure like struct _somename { int somenuml; int somenum2; int somenum3; char databuffer1[100]; // very long struct }; // initialize struct struct _somename mystruct; mystruct.somename = 1; //------ // ans finaly open some file and write to file fwrite(&mystruct,1,sizeof(struct _somename)); Now I want to convert same c programme in java due to some technical reason
Trioum
trioum wrote:
Now I want to convert same c programme in java due to some technical reason
Then you have some work to do. The original implementation made assumptions about the layout of the data in memory. Or maybe they just completely ignored it because they didn't understand it at all. And you must determine what that layout is and then match it exactly. For starters you will need to know the size of 'int' and whether it is big endian or little endian. You need to determine the exact binary format that the 'int' takes in memory so you can determine how it would be written to a file. And you must do the same for every other data item in the struct. Finally you must account for the fact that the struct might be padded at the end. So there might be one or more random bytes which are not explicitly represented in the structure.
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Actually I have I programme which write in file with some fixed header in files . which is in form of structure like struct _somename { int somenuml; int somenum2; int somenum3; char databuffer1[100]; // very long struct }; // initialize struct struct _somename mystruct; mystruct.somename = 1; //------ // ans finaly open some file and write to file fwrite(&mystruct,1,sizeof(struct _somename)); Now I want to convert same c programme in java due to some technical reason
Trioum
It's not that bad - C/C++ structs and classes are virtually identical - convert these to classes in Java and make adjustments if you're placing them on the stack in C++ - there is no automatic copy construction or assignment in Java:
public class _somename
{
public int somenuml;
public int somenum2;
public int somenum3;
public String databuffer1 = new String(new char[100]);
// very long struct
}public static void test()
{
// initialize struct
_somename mystruct = new _somename();
mystruct.somename = 1;
}David Anton Convert between VB, C#, C++, & Java www.tangiblesoftwaresolutions.com
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It's not that bad - C/C++ structs and classes are virtually identical - convert these to classes in Java and make adjustments if you're placing them on the stack in C++ - there is no automatic copy construction or assignment in Java:
public class _somename
{
public int somenuml;
public int somenum2;
public int somenum3;
public String databuffer1 = new String(new char[100]);
// very long struct
}public static void test()
{
// initialize struct
_somename mystruct = new _somename();
mystruct.somename = 1;
}David Anton Convert between VB, C#, C++, & Java www.tangiblesoftwaresolutions.com
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trioum wrote:
still not able to write in the file
What does this mean? Please give a proper explanation of your problem so poeple can try and help you.
Just say 'NO' to evaluated arguments for diadic functions! Ash
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Make your class serialisable and write it to a binary buffer. Sorted.
Panic, Chaos, Destruction. My work here is done. or "Drink. Get drunk. Fall over." - P O'H
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Make your class serialisable and write it to a binary buffer. Sorted.
Panic, Chaos, Destruction. My work here is done. or "Drink. Get drunk. Fall over." - P O'H
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trioum wrote:
can you send me the piece of code for writing class content to the file
0. Define the class as
implements Serializable:class Foo implements Serializable
{
private int bar;
// stuff// other stuff
}1. Write it to a binary buffer:
Foo foo = new Foo(42);
try
{
java.io.ObjectOutputStream os =
new java.io.ObjectOutputStream(
new java.io.FileOutputStream("foobar.dat"));
os.writeObject(foo);
} catch (java.io.IOException e)
{
e.printStackTrace();
} finaly
{
os.close();
}That's hard how?
Panic, Chaos, Destruction. My work here is done. or "Drink. Get drunk. Fall over." - P O'H
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trioum wrote:
can you send me the piece of code for writing class content to the file
0. Define the class as
implements Serializable:class Foo implements Serializable
{
private int bar;
// stuff// other stuff
}1. Write it to a binary buffer:
Foo foo = new Foo(42);
try
{
java.io.ObjectOutputStream os =
new java.io.ObjectOutputStream(
new java.io.FileOutputStream("foobar.dat"));
os.writeObject(foo);
} catch (java.io.IOException e)
{
e.printStackTrace();
} finaly
{
os.close();
}That's hard how?
Panic, Chaos, Destruction. My work here is done. or "Drink. Get drunk. Fall over." - P O'H
That won't compile. os is out of scope in the finally block.
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That won't compile. os is out of scope in the finally block.
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trioum wrote:
can you send me the piece of code for writing class content to the file
0. Define the class as
implements Serializable:class Foo implements Serializable
{
private int bar;
// stuff// other stuff
}1. Write it to a binary buffer:
Foo foo = new Foo(42);
try
{
java.io.ObjectOutputStream os =
new java.io.ObjectOutputStream(
new java.io.FileOutputStream("foobar.dat"));
os.writeObject(foo);
} catch (java.io.IOException e)
{
e.printStackTrace();
} finaly
{
os.close();
}That's hard how?
Panic, Chaos, Destruction. My work here is done. or "Drink. Get drunk. Fall over." - P O'H
there is difference i getting when writing using c and java following lines shows the difference when I use the c code struct _Foo { int one; int two; char buffer[50]; } ; struct _Foo foo; memset(&foo,'0/',sizeof(_Foo)); foo.one = 2; foo.two = 3; strcpy(foo.buffer,"my name is trioum"); FILE *fp; fp = fopen("cfile.txt","wb"); if(fp) { fwrite(&foo,sizeof(struct _Foo),1,fp); fclose(fp); } result in the file I get my name is trioum ////////////////////////////////// but when I write the same code in java public static class _Foo implements Serializable { public int one; public int two; public String buffer = new String(new char[50]); } ObjectOutputStream outputStream = null; try { outputStream = new ObjectOutputStream(new FileOutputStream("javafile.txt")); _Foo Foo = new _Foo(); Foo.one = 2; Foo.two = 3; Foo.buffer = "my name is trioum"; outputStream.writeObject(Foo); } catch (FileNotFoundException ex) { ex.printStackTrace(); } catch (IOException ex) { ex.printStackTrace(); } I get the result in javafile.txt ¬í sr Main$_FooDpÕGT¯_ I oneI twoL buffert Ljava/lang/String;xp t my name is trioum But I want the result as seen in cfile.txt by c code How can I solve the problem
Trioum
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there is difference i getting when writing using c and java following lines shows the difference when I use the c code struct _Foo { int one; int two; char buffer[50]; } ; struct _Foo foo; memset(&foo,'0/',sizeof(_Foo)); foo.one = 2; foo.two = 3; strcpy(foo.buffer,"my name is trioum"); FILE *fp; fp = fopen("cfile.txt","wb"); if(fp) { fwrite(&foo,sizeof(struct _Foo),1,fp); fclose(fp); } result in the file I get my name is trioum ////////////////////////////////// but when I write the same code in java public static class _Foo implements Serializable { public int one; public int two; public String buffer = new String(new char[50]); } ObjectOutputStream outputStream = null; try { outputStream = new ObjectOutputStream(new FileOutputStream("javafile.txt")); _Foo Foo = new _Foo(); Foo.one = 2; Foo.two = 3; Foo.buffer = "my name is trioum"; outputStream.writeObject(Foo); } catch (FileNotFoundException ex) { ex.printStackTrace(); } catch (IOException ex) { ex.printStackTrace(); } I get the result in javafile.txt ¬í sr Main$_FooDpÕGT¯_ I oneI twoL buffert Ljava/lang/String;xp t my name is trioum But I want the result as seen in cfile.txt by c code How can I solve the problem
Trioum
That's because you are serializing the whole Foo object, which is not what you want. I'm not going to write the whole thing for you but I think I would make Foo look something like this:
public class Foo {
public char one;
public char two;
public String buffer;
... etc ...public String toExternalForm() {
StringBuilder sb = new StringBuilder();
sb.append(one);
sb.append(two);
sb.append(buffer);
... etc ...
return sb.toString();
}}
Then to use it:
foo.one = 2;
foo.two = 3;
foo.buffer = "something";
bw = new BufferedWriter(...etc...);
bw.write(foo.toExternalForm());
bw.flush();That's basically it, you can look up BufferedWriter and whatever else you need and you might want to be a bit more intelligent about handling nulls. (I am using char instead of int in the class Foo because if we use int then StringBuilder would give us 23something which is not what you want, if I have understood correctly.)
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That's because you are serializing the whole Foo object, which is not what you want. I'm not going to write the whole thing for you but I think I would make Foo look something like this:
public class Foo {
public char one;
public char two;
public String buffer;
... etc ...public String toExternalForm() {
StringBuilder sb = new StringBuilder();
sb.append(one);
sb.append(two);
sb.append(buffer);
... etc ...
return sb.toString();
}}
Then to use it:
foo.one = 2;
foo.two = 3;
foo.buffer = "something";
bw = new BufferedWriter(...etc...);
bw.write(foo.toExternalForm());
bw.flush();That's basically it, you can look up BufferedWriter and whatever else you need and you might want to be a bit more intelligent about handling nulls. (I am using char instead of int in the class Foo because if we use int then StringBuilder would give us 23something which is not what you want, if I have understood correctly.)
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is there any C structure equivalant in java how to write following struct { int data char buffer[100]; }; equivalent in java
Trioum
Why not use a
class?class xyz
{
public int data;
public string buffer;
};"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius