Thread: string search question...

>> preferred method
The preferred method is one that you are comfortable using, and does it's job correctly and efficiently.

You can use strstr() to search the string.

There is no need to actually copy from the array you're searching, as you already know what that text is.

Code:

#include <stdio.h>
#include <string.h>

int main(void)
{
  char name[] = "@hammer@";
  char foo[BUFSIZ];
	
  if (strstr(name, "hammer"))
  {
    strcpy (foo, "hammer");
    puts(foo);
  }
	
  return(0);
}

There are other ways...

If all you want is a string between @'s you can do something along the lines of this:

Code:

Tue Sep 23 7:18:37pm
sangut: ~/misc
> cat rp.c
#include <stdio.h>
#include <string.h>

char *copy(char *string, char *buffer) {
  size_t a;
  size_t b;

  a = strspn(string, "@");
  b = strcspn(string + a, "@");
  strncpy(buffer, string + a, b);
  buffer[b] = '\0';

  return buffer;
}

int main ( ) {
  char buffer[7];

  copy("@foobar@", buffer);
  puts(buffer);

  return 0;
}

If you want to copy everything between the @ and the @, here is another idea.

Code:

#include <stdio.h>

int main(void)
{
   const char text[] = "@foobar@";
   char found[ sizeof text ];
   if ( sscanf(text, "@%[^@]@", found) == 1 )
   {
      puts(found);
   }
   return 0;
}


/* my output
foobar
*/

If you want to copy everything between the @ and the @, here is another idea.

Posted more for fun than anything else...

Code:

#include <stdio.h>

char *foo(const char *input, char delim, char *output, size_t outsize)
{
  /* Returns NULL if 2 delimiters aren't found or we run out of room in the output buffer */
  char *p = output;
  while (*input && *input != delim) input++;
  while (*input && *++input != delim && --outsize) *output++ = *input;
  *output = '\0';
  if (*input != delim)
    p = NULL;
  return p;
}

int main(void)
{
  char name[] = "@hammer@";
  char bar[BUFSIZ];

  printf ("%s -->  %s\n", name, foo(name, '@', bar, sizeof(bar)));

  return(0);
}

You aren't posting much code. I, and possibly others, may be less inclined to offer assistance if you don't show much of an effort.

However, the following should demonstrate some sort of starting point.

Code:

/*
 * @DESCRIPTION@
 * Print the line following a line containing at least one keyword.
 */
#include <stdio.h>
#include <string.h>

/* @FUNCTION@ */
void foo(const char *line)
{
   fputs(line, stdout); /* or do further processing */
}

/* @FUNCTION@ */
void bar(const char *filename, const char *keyword[], size_t size)
{
   FILE *file = fopen(filename, "r");
   if ( file != NULL )
   {
      char line[BUFSIZ];
      int printnext = 0;
      while ( fgets(line, sizeof line, file) != NULL )
      {
         size_t i;
         if ( printnext )
         {
            foo(line); /* keyword found in previous line */
            printnext = 0;
         }
         for ( i = 0; i < size; ++i )
         {
            if ( strstr(line, keyword[i]) != NULL )
            {
               printnext = 1; /* found keyword in current line */
               break;
            }
         }
      }
   }
}

/* @FUNCTION@ */
int main(void)
{
   const char *keyword[] = { "@FUNCTION@", "@DESCRIPTION@" };
   bar(__FILE__, keyword, sizeof(keyword)/sizeof(*keyword));
   return 0;
}

/* my output
 * Print the line following a line containing at least one keyword.
void foo(const char *line)
void bar(const char *filename, const char *keyword[], size_t size)
int main(void)
   bar(__FILE__, keyword, sizeof(keyword)/sizeof(*keyword));
*/

>>When I locate the string I want to copy, >>how do I copy it
Methods as above, including strcpy() etc.

>>and into what?
Whatever you like, but it'll have to ultimately be another char array.

I have tried to develop the following algorithm for my proble, but i need help putting it into codes. I was told by a prof that i can achieve it with 8-10 lines of codes.
Then i tried, but i don't think my code's right, cuz it didn't work.


- Use char buf[BUFSIZ]
-Proceed to read each line from stdin, using fgets in a while loop
-Look through each character in the line for the string i want
-Using strncmp, check if you find a match for the old string
-if the "old" string is found
- print out the "new" string in its place
-increase buf by number of characters in the "new" string
-else if you can't find a match, just print the characters.


Now here's how i put it into code and it won't work.
Help please!!

Thanks a lot people.
I had posted my problem before, it's just not working yet. I need to replace an old string with a new one from a line as read in from stdin, onto the stdout.