в 14:20, 25 мая 2010

2010-05-25T14:20:56Z

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2010-05-25T10:22:12Z

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==Reposition file pointer to a saved location: how to use fsetpos==

<source lang="cpp">

#include <stdio.h>
int main ()
{
FILE * file;
fpos_t pos;
file = fopen ("my.txt", "w");

fgetpos(file, &pos);

fputs ("That is a line." ,file);

fsetpos (file, &pos);
fputs ("This", file);

fclose (file);
return 0;
}

</source>

==Reset file position indicator to start of the file==

<source lang="cpp">
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(void)
{
char str[80];
FILE *fp;
if((fp = fopen("TEST", "w+"))==NULL) {
printf("Cannot open file.\n");
exit(1);
}
do {
printf("Enter a string (CR to quit):\n");
gets(str);
strcat(str, "\n"); /* add a newline */
fputs(str, fp);
} while(*str!="\n");
rewind(fp); /* reset file position indicator to
start of the file. */
while(!feof(fp)) {
fgets(str, 79, fp);
printf(str);
}
return 0;
}

</source>

== Return the current position in a stream: how to use ftell==

<source lang="cpp">

#include <stdio.h>
int main ()
{
FILE *file;
long size;
file = fopen ("my.txt","rb");

if (file == NULL)
perror ("Error reading my.txt.");
else {
fseek (file, 0, SEEK_END);
size = ftell(file);

fclose (file);
printf ("Size of my.txt is %ld bytes.\n",size);
}
return 0;
}

</source>

==Set the file pointer to the beginning of a stream: how to use rewind==

<source lang="cpp">

#include <stdio.h>
int main ()
{
int n;
FILE *file;
char buffer[27];
file = fopen ("my.txt", "w+");

for ( n="A" ; n<="Z" ; n++)
fputc ( n, file);

rewind ( file );
fread (buffer, 1, 26, file);
fclose ( file );
buffer[26] = "\0";
puts ( buffer );

return 0;
}

</source>

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C/File/File Pointer - История изменений

в 14:20, 25 мая 2010

Admin: 1 версия: Импорт контента...