A structure is a collection of variables under a single name. These variables can be of different types, and each has a name which is used to select it from the structure. A structure is a convenient way of grouping several pieces of related information together.

Further Uses of Structures
A structure is a good way of storing related data together.It is also a good way of representing certain types of information. Complex numbers in mathematics inhabit a two dimensional plane (stretching in real and imaginary directions). These could easily be represented here by

struct complex
{
double real;
double imag;
}
doubles have been used for each field because their range is greater than floats and because the majority of mathematical library functions deal with doubles by default.
Structures can also be used as
1. Members of other structures.
2. Arrays of structures are possible, and are a good way of storing lists of data with regular fields,
such as databases.
3. Use to creat link list, trees and other connected structures.

1.2
date 2014.03.27.10.38.34; author root; state Exp;
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1.1
date 2014.03.26.10.31.39; author root; state Exp;
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desc
@complete program without display fuction
@

1.2
log
@this is complete program
@
text

1.1
date 2014.03.25.14.53.42; author root; state Exp;
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desc
@sum of two distances using struct and function
@

1.1
log
@Initial revision
@
text

2.gets() :-it takes single argument.The argument must be a data item representing a string.
gets() doesn’t allow to specify the length of the buffer to store the string in.
This would allow user to keep entering data past the end of your buffer…
Never use gets().Because it is impossible to tell without
knowing the data in advance how many characters gets() will
read, and because gets() will continue to store characters
past the end of the buffer, it is extremely dangerous to
use.
It has been used to break computer security. Use
fgets() instead.

3.fgets():-This function read bytes from stream into the array pointed to by s, until n-1 bytes are read,
or a is read and transferred to s, or an end-of-file condition is encountered.

RETURN VALUE :Both gets() and fgets() return a pointer to the string passed.
and on failure of function gets() and fgets() returns NULL.

4.getc() :-returns a character from the specified file.

5.fgetc():-it’s equivalent to the same getc().Only the implementation of the two functions differs.

6.fgetc() and getc() are equivalent, except that getc may be implemented as a macro in some libraries.

7.getchar():- this is similiar to getc().it return a char form stdin.

8.All these above function getc(),fgetc(),getchar() return EOF on error.

9.ungetc() :-we know how getc() reads the next character from a file stream,this ungetc() is the opposite of getc()
it pushes a character back into the file stream so that it will show up again on the very next read from
the stream, as if you’d never gotten it from getc() in the first place.

Now ,suppose you have a stream of data that you’re reading a character at a time, and you won’t know to
stop reading until you get a certain character, but you want to be able to read that character again
later. You can read the character, see that it’s what you’re supposed to stop on, and then ungetc() it
so it’ll show up on the next read.
The standard only guarantees that you’ll be able to push back one character.
RETURN VALUE:On success, ungetc() returns the character you passed to it. On failure, it returns EOF.

1.1
date 2014.03.19.09.49.44; author root; state Exp;
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desc
@program to read file from n pos
@

1.1
log
@Initial revision
@
text

1.1
date 2014.03.19.09.15.04; author root; state Exp;
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desc
@reading form file and writing into another using fgetc() and fputc()
@

1.1
log
@Initial revision
@
text

1.2
date 2014.03.15.16.06.03; author root; state Exp;
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1.1
date 2014.03.14.06.52.50; author root; state Exp;
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desc
@this is the initial version,file created and open using function().
@

1.2
log
@implemented masterarray using function
@
text
@#include”header.h”

int main(int argc, char *argv[])
{
int fd,ret;

if(argc !=2)
{
printf(“insufficient arguments !!”);
goto out;
}
fd=openfile(argv[1]);
masterarray(fd);
return 0;
out:
return -1;

}
int openfile(char *ipfile)
{
int fd;
fd = open(ipfile,O_RDONLY);

if(fd<0)
{
perror("open");
goto out;
}
printf("file discriptor : %d",fd);
return fd;
out:
return 0;
}
int masterarray(int fd)
{
int ret,i,ndc=0;
char ch;
char masterarray[128];
do
{
ret=read(fd,&ch,1);
if(ret<0)
{
perror("read");
close(fd);
goto out;
}
if(ch!=10)
{
masterarray[ndc]=ch;
ndc++;
}
}while(ch!=10);
for(i=0;i<ndc;i++)
printf("read %d char ch=%c \n",ret,masterarray[i]);
out:
return -1;
return 0;
}
@

printf("The array is :\n");
for(i=0; i < size; i++)
printf("arr[%d]:%d\n",i,arr[i]);

printf("String after bubble sort ");
for(j=0 ; j<size ; j++)
{
for(i=0 ; i arr[i+1])
{
temp=arr[i+1];
arr[i+1]=arr[i];
arr[i]=temp;
}
}
for(i=0 ; i<size ; i++)
printf("arr[%d] :%d\n ",i,arr[i]);

return 0;
}

1.1
date 2014.03.14.06.52.50; author root; state Exp;
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desc
@this is the initial version,file created and open using function().
@

1.1
log
@Initial revision
@
text
@#include”header.h”

int main(int argc, int *argv[])
{
int fd,ret;
char ch;
if(argc !=2)
{
printf(“insufficient arguments”);
goto out;
}
fd=openfile(argv[1]);
do
{
ret=read(fd,&ch,1);
if(ret<0)
{
perror("read");
close(fd);
goto out;
}
if(ch!=10)
{
masterarray[ndc]=ch;
ndc++;
}
}while(ch!=10);
for(i=0;i<ndc;i++)
printf("read %d char ch=%c \n",ret,masterarray[i]);
return 0;
out:
return -1;

}
int openfile(char *ipfile)
{
int fd;
fd = open(ipfile,O_RDONLY);
if(fd<0)
{
perror("open");
goto out;
}
printf("file discriptor : %d",fd);
return fd;
out:
return 0;
}
@

1.1
date    2014.03.12.12.30.53;    author root;    state Exp;
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next    ;

desc
@i have created,read and write a file using function.
@

1.1
log
@Initial revision
@
text