"UNIX"
: . .-31
..
: ..
2
2014
:
1. 1.................................................................................................................................................. 3
2. 2.................................................................................................................................................. 6
:.................................................................................................................................... 9
1
C++ g++ UNIX, :
- list : , , ;
- list ;
- list1 list, ʔ.
.
Unix
:
int open (const char* path, int accesmode, int permission) - fcntl.h, path - , permission 0.
: _RDONLY - , _WRONLY - , O_RDWR .
, O_CREAT - , . -1 .
int create (const char* path, int accesmode) - .
long read (int fdesc, void* buf, int size) - .
unistd.h, fdesc - , buf - , , size - , . .
long write (int fdesc, const void* buf, int size) - .
- unistd.h, read. , .
long lseek (int fdesc, long pos, int whence) - - . - unistd.h, pos - , . whence : SEEK_CUR - ; SEEK_SET - ; SEEK_END - . .
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <fcntl.h>
#include <string.h>
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#define N 5
struct TComp
{
char* name[15];
int count;
float price;
} Comp, fcomp;
char* fname="list";
void make_file()
{
int f=open(fname, O_WRONLY|O_CREAT,0);
if (f==-1)
{
perror(" ");
exit (1);
}
for(int i=0; i<N; i++)
{
puts (" : ");
scanf("%s",&Comp.name);
puts(" : ");
scanf("%i %f", &Comp.count, &Comp.price);
write(f, &Comp, sizeof(Comp));
printf("name=%s; count=%i; price=%f;\n", Comp.name, Comp.count, Comp.price);
}
close(f);
}
void max_price()
{
fcomp.price = 0;
int f1 = open(fname, O_RDONLY, 0);
if (f1==-1)
{
perror(" ");
exit (1);
}
while (read(f1, &Comp, sizeof(Comp)))
{
if (Comp.price > fcomp.price)
{
fcomp.name = Comp.name;
fcomp.count = Comp.count;
fcomp.price = Comp.price;
}
printf("%s price is %f.\n", Comp.name, Comp.price);
}
printf("Computer %s has maximum price of %f", fcomp.name, fcomp.price);
close(f1);
}
void prosmotr()
{
int f2=open(fname, O_RDONLY,0);
if (f2==-1)
{
perror(" ");
exit (1);
}
while (read(f2, &Comp, sizeof(Comp)))
{
printf("name=%s; count=%i; price=%f;\n", Comp.name, Comp.count, Comp.price);
}
close(f2);
}
void main()
{
int option;
puts(" : ");
puts("1- ; 2- . ; 3- :");
scanf("%i", &option);
switch(option)
{
case 1: make_file(); break;
case 2: max_price(); break;
case 3: prosmotr(); break;
}
}
2
. :
- .
- , . .
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. , , . : AF_UNIX ( - Unix) AF_INET ( - - ).
, . - , , . - , . - , , . , , , , .
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, Unix- . - TCP, -UDP.
