c strings

is there a function in string.h for substrings on a an array of characters?

strstr() maybe?

You may want to try looking at this:
C String Functions
I cooked this up real quick, I'm not totally sure if this is what you wanted though:

Code:

---

#include <stdio.h>
#include <stdlib.h>

char *getSubstring(char *haystack, int start, int end);

int main(void) {
 char *myString = "Hello World";
 char *mySubString = NULL;

 if( (mySubString = getSubstring(myString, 1, 4)) == NULL) {
  puts("Substring error");
  return 0;
 }

 puts(mySubString);
 return 0;
}

char *getSubstring(char *haystack, int start, int end) {
 char *substring = malloc(255 * sizeof(*substring));

 if(end < start)
  return NULL;

 int i, location=0;
 for(i=start; i<=end; ++i) {
  if(haystack[i] == '\0') return NULL;

  substring[location++] = haystack[i];
 }
 substring[location] = '\0';
 return substring;
}

---

The output is:

Code:

---

kleid@Shiva:~/Programming/Laboratory$ ./a.out
ello

---

You may need to be more specific, but it sounds to me like you want to tokenize a string. If you have a string containing several substrings, separated by a certain character, strtok will replace that character with a null character, and return a pointer to the beginning of that 'token'. You do this a couple of times, and you've "tokenized" a string.

could you explain to me thw use of malloc in the post by Kleid-0?