in
printf(“%s”, address_book_content);
pos = ftell(show_address_book);
fseek(show_address_book, 27, pos); /// 27 in just a random number, I just want it to change the position of the cursor in the file
printf(“%s”, address_book_content);
fseek не меняет address_book_content
, поэтому вы пишете два раза одно и то же
, которое необходимо прочитать в файле изпозиция, которую вы вычислили, чтобы иметь возможность написать то, что вы прочитали, изменив address_book_content
, если вы все еще печатаете ее.Или просто прочитайте и распечатайте следующие строки после той, которую вы прочитали:
while ( (fgets(address_book_content, MAX_VALUE_FOR_ARRAYS, show_address_book) != NULL)
{
if ( (string_exists = strstr(address_book_content, contact_name) != NULL)
{
fputs(address_book_content, stdout); /* fputs rather printf to not write again a \n */
/* supposing it was the firstname there are 5 lines after to read and print */
fputs(fgets(address_book_content, MAX_VALUE_FOR_ARRAYS, show_address_book), stdout);
fputs(fgets(address_book_content, MAX_VALUE_FOR_ARRAYS, show_address_book), stdout);
fputs(fgets(address_book_content, MAX_VALUE_FOR_ARRAYS, show_address_book), stdout);
fputs(fgets(address_book_content, MAX_VALUE_FOR_ARRAYS, show_address_book), stdout);
fputs(fgets(address_book_content, MAX_VALUE_FOR_ARRAYS, show_address_book), stdout);
break;
}
}
Предупреждение strstr - неправильный путь, потому что он поймает имя, содержащее ожидаемую, длянапример, имя IamNotTonyAtAll совпадение Тони с использованием strstr
Конечно, каждый раз при поиске файла довольно дорого читатьдля имени ...
Полное предложение:
#include <stdio.h>
#include <string.h>
#define MAX_VALUE_FOR_ARRAYS 1000
int main()
{
FILE * fp = fopen("addressBook.txt", "r");
if (fp == NULL)
puts("cannot read addressBook.txt");
else {
/* use static vars to not take place into the stack */
static char contact_name[MAX_VALUE_FOR_ARRAYS];
printf("Enter the name of the contact you want to search : ");
if (scanf("%s", contact_name) != 1)
puts("invalid input");
else {
static char line1[MAX_VALUE_FOR_ARRAYS];
static char line2[MAX_VALUE_FOR_ARRAYS];
/* to have \n at the end like the read lines, it is also possible
to read the name with fgets but in case of extra spaces at the end it is not found */
strcat(contact_name, "\n");
while ((fgets(line1, MAX_VALUE_FOR_ARRAYS, fp) != NULL) &&
(fgets(line2, MAX_VALUE_FOR_ARRAYS, fp) != NULL))
{
if ((strcmp(line1 + /*bypass "First Name : "*/ 13, contact_name) == 0) || /* first name */
(strcmp(line2 + /*bypass "Last Name : "*/ 12, contact_name) == 0)) { /* last name */
/* that one */
fputs(line1, stdout);
fputs(line2, stdout);
if (fgets(line1, MAX_VALUE_FOR_ARRAYS, fp) != NULL) {
fputs(line1, stdout);
if (fgets(line1, MAX_VALUE_FOR_ARRAYS, fp) != NULL) {
fputs(line1, stdout);
if (fgets(line1, MAX_VALUE_FOR_ARRAYS, fp) != NULL) {
fputs(line1, stdout);
if (fgets(line1, MAX_VALUE_FOR_ARRAYS, fp) != NULL) {
fputs(line1, stdout);
}
}
}
}
break;
}
else {
fgets(line1, MAX_VALUE_FOR_ARRAYS, fp);
fgets(line1, MAX_VALUE_FOR_ARRAYS, fp);
fgets(line1, MAX_VALUE_FOR_ARRAYS, fp);
fgets(line1, MAX_VALUE_FOR_ARRAYS, fp);
}
}
fclose(fp);
}
}
return 0;
}
Примеры:
pi@raspberrypi:/tmp $ ./a.out
Enter the name of the contact you want to search : Tony
First Name : Tony
Last Name : Stark
Address : Malibu
Phone number : 10203044032
E-mail : tony.stark@jarvis.com
Company / Place of work : Stark Industries
pi@raspberrypi:/tmp $ ./a.out
Enter the name of the contact you want to search : Stark
First Name : Tony
Last Name : Stark
Address : Malibu
Phone number : 10203044032
E-mail : tony.stark@jarvis.com
Company / Place of work : Stark Industries
pi@raspberrypi:/tmp $ ./a.out
Enter the name of the contact you want to search : Bruno
First Name : Bruno
Last Name : Pages
Address : somewhere in France
Phone number : 123456789
E-mail : me@hiddenAddress.fr
Company / Place of work : BoUML unlimited
Предположим, addressBook.txt содержит:
First Name : Tony
Last Name : Stark
Address : Malibu
Phone number : 10203044032
E-mail : tony.stark@jarvis.com
Company / Place of work : Stark Industries
First Name : Bruno
Last Name : Pages
Address : somewhere in France
Phone number : 123456789
E-mail : me@hiddenAddress.fr
Company / Place of work : BoUML unlimited