c - How to get word before and after the current word in a file? -

i have file, "data.txt" consists of following: http://pastebin.com/fy9ztqx6

i'm trying word before , after "<". old word being 1 on left , new word being 1 on right. have far:

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <ctype.h>  /* name: marcus lorenzana assignment: final */  //binary tree struct hold left , right node //as word , number of occurrences typedef struct node {     char *word;     int count;     struct node *left;     struct node *right; } node;  //,.?!:;- int punctuation[7];   void insert(node ** dictionary, node * entry); char* readfile(char* filename); void printdictionary(node * tree); void tolower(char** word); void getreplacementwords(char *filecontents, char **newword, char **oldword)  ;   int main() {      char *word;     char* filecontents = readfile("data.txt");     char* oldword;     char* newword;      //create dictionary node     node *dictionary;     node *entry;      //read words , punctuation in text file     word = strtok (filecontents, " \n");      dictionary = null;      while (word != null)     {         //word = strlwr(word);          entry = (node *) malloc(sizeof(node));         entry->left = entry->right = null;         entry->word = malloc(sizeof(char)*(strlen(word)+1));         entry->word = word;         insert(&dictionary,entry);         word = strtok (null, " \n");     }      //printdictionary(dictionary);      filecontents = readfile("data.txt");      getreplacementwords(filecontents,&newword,&oldword);         return 0; }  void insert(node ** dictionary, node * entry) {     if(!(*dictionary))     {         *dictionary = entry;         entry->count=1;         return;     }       int result = strcmp(entry->word,(*dictionary)->word);      if(result<0){         insert(&(*dictionary)->left, entry);         entry->count++;      }     else if(result>0){         insert(&(*dictionary)->right, entry);         entry->count++;      } else {         entry->count++;      }  }  //put file contents in string strtok char* readfile(char* filename) {     file* file = fopen(filename,"r");     if(file == null)     {         return null;     }      fseek(file, 0, seek_end);     long int size = ftell(file);     rewind(file);      char* content = calloc(size + 1, 1);      fread(content,1,size,file);      return content; }  void printdictionary(node * dictionary) {     if(dictionary->left) {         printdictionary(dictionary->left);     }      printf("%s\n",dictionary->word);      if(dictionary->right) {         printdictionary(dictionary->right);     } }   void getreplacementwords(char *filecontents, char **newword, char **oldword) {     char *word;     word = strtok (filecontents, " \n");      while (word != null)     {         printf("\n%s",word);          int result = strcmp(word,"<");          if (result == 0) {             printf("\nfound replacement identifier");          }         word = strtok (null, " \n");     } } 

you can use fscanf(filename , "%s < %s" , firststringcontainer , secondstringcontainer)

after using fseek line containing < character string before < stored in firststringcontainer , 1 after in secondstringcontainer here's code recommand use :

int found = 0; char buffer[chooseyoursize]; char firststringcontainer[chooseyoursize] , secondstringcontainer[chooseyoursize]; while(fgets(buffer , sizeof(buffer) , filename) != null) {     if(strchr(buffer , '<'))     {          found++;          break;     } } if(found) {      fscanf(file , "%s < %s" , firststringcontainer , secondstringcontainer); } 

of course works if lines targeted contains 3 elements string < string case here