C - Find a word and get the next two - c

Question

I am parsing a file in C, line by line. Here is an exemple of what I am trying to do :
I have a line for example :
word word word WORDTOFIND: word1 word2 word word
What I want to do is : When I find the word WORDTOFIND, get the two next words (word1 and word2 in this case) of the line. Is there an easy way to do that in C ? I know about the strstr function, but I don't find a way to get the next two words word1 and word2 after I found the good one.

Answer 1

One approach would be this:
int main(void)
{
char *str = "rated rat cat bat hat";
char *key = "rat ";
char *pointer = NULL;
char nwords = 2;
if ((pointer = strstr(str, key)) != NULL)
{
while (*pointer != ' ') pointer++;
while (nwords >= 0)
{
printf("%c", *pointer);
if (*pointer == ' ') {
nwords--;
} else if (*pointer == '\0') {
exit(0);
}
pointer++;
}
}
}

Answer 2

You can try an aproach like this, using strtok to parse the words at every space. This code also uses malloc and realloc to allocate space for an array of strings, and grows it when needed.
The code looks like this:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#define MAXCHAR 100
void exit_if_null(void *ptr, const char *msg);
char *stripped_word(char *word);
int
main(int argc, char const *argv[]) {
FILE *filename;
char line[MAXCHAR];
char *word, *newword;
char **allwords;
int init_size = 8, count = 0, i;
const char *key = "WORDTOFIND";
filename = fopen("files.txt", "r");
if (filename == NULL) {
fprintf(stderr, "%s\n", "Error reading file!");
exit(EXIT_FAILURE);
}
allwords = malloc(init_size * sizeof(*allwords));
exit_if_null(allwords, "Initial Allocation");
while (fgets(line, MAXCHAR, filename) != NULL) {
word = strtok(line, " \n");
while (word != NULL) {
if (count == init_size) {
init_size *= 2;
allwords = realloc(allwords, init_size * sizeof(*allwords));
}
allwords[count] = malloc(strlen(word)+1);
exit_if_null(allwords[count], "Initial Allocation");
newword = stripped_word(word);
strcpy(allwords[count], newword);
count++;
word = strtok(NULL, " \n");
free(newword);
}
}
for (i = 0; i < count; i++) {
if (strcmp(key, allwords[i]) == 0) {
printf("Next two words:\n");
printf("%s\n", allwords[i+1]);
printf("%s\n", allwords[i+2]);
}
free(allwords[i]);
allwords[i] = NULL;
}
free(allwords);
allwords = NULL;
return 0;
}
void
exit_if_null(void *ptr, const char *msg) {
if (!ptr) {
printf("Unexpected null pointer: %s\n", msg);
exit(EXIT_FAILURE);
}
}
char
*stripped_word(char *word) {
int i, pos = 0;
char *result;
result = malloc(strlen(word)+1);
exit_if_null(result, "Initial Allocation");
for (i = 0; word[i] != '\0'; i++) {
if (isalpha(word[i]) || isdigit(word[i])) {
result[pos++] = word[i];
}
}
result[pos] = '\0';
return result;
}