How to reread the end of a buffer in C?

See more:

C

FileIO

buffer

I'm using a buffer to temporarily store a certain bytes of data(characters) from a file. I just want to find out whether a particular word is present in the file. Let's say, I'm searching for a word 'Apple' and I'm storing a string from the file into the buffer which has the first half "App" at the end of the buffer and "le" in the next buffer. I just want to make sure that these words are not missed out What can I do to reread a particular length at the end of the buffer. How can I modify the following code?

What I have tried:

while(feof(fptr)==0){
		char * result;
		char line[100];
		result = fgets( line, sizeof( line ), fptr );
	if ( result == NULL ){
        break;
   	}
   	line[strcspn( line, "\n" ) ] = '\0';
   	token = strtok(line," \t,:;\'\"\?!-_|\\><~@#$%^&*()+{}[].=1234567890");
   	while( token != NULL ) {
      	printf( " %s\n", token );
        if(strcasecmp(token,word)==0){
        	count++; //counts the number of occurrence of the word 
		}
        token = strtok(NULL," \t,:;\'\"\?!-_|\\><~@#$%^&*()+{}[].=1234567890");
   }
	}