Help...using strings and txt files

I have 99% of the program done and all I have left is to write the rest of the functions to replace and process the tags. What I was asked to do was to write a program to use 3 txt files. one to read in, one to contain tags to replace those in the txt file and one to print to

Code:

---

#include "frmlet.h"

//reads in the whole form
void read_letter(string form_txt,
        char get_form[MAX_LINE][MAX_CHAR],
        int *form_count)
{
        int i;
        freopen("form.txt","r",stdin);
        scanf("%i", form_count);

        for (i=0; i<*form_count; i++)
        {
                scanf(" %119[6\n]", get_form[i]);
        }
return;
}

//reads in the tags and replacement names
void read_tag(string tag_txt,
        char get_tag[MAX_LINE][MAX_CHAR],
        char replace[MAX_LINE][MAX_CHAR],
        int *tag_count)
{
        int i;
        char end[] = ">";

        freopen("tags.txt","r",stdin);
        scanf("%i", tag_count);

        for (i=0; i<*tag_count; i++)
        {
                scanf(" %10[^>]> %25[^\n]", get_tag[i], replace[i]);
                strcat(get_tag[i], end);
        }

return;
}

//replaces the form tags with the names
void string_replace(char get_form[MAX_LINE][MAX_CHAR],
        char get_tag[MAX_LINE][MAX_CHAR])
{
        char temp[MAX_CHAR] = "";
        char *P, *Q, *R;

        P= strstr(...,...);

        while (P!= NULL)
        {
               
                Q = P+strlen(get_tag);
                *P = '\n';

                temp[0] = '\0';
        }
return;
}
//processes the replacements
void process(char get_form[MAX_LINE][MAX_CHAR],
        int form_count,
        char get_tag[MAX_LINE][MAX_CHAR],
        char replace[MAX_LINE][MAX_CHAR],
        int tag_count)
{
        int i,j;

        for (i=0; i<form_count; i++)
                for (j=0; j<tag_count; j++)
                {
                        string_replace();
                }
return;
}

//prints the new form to a text file
void print_letter(char get_form[MAX_LINE][MAX_CHAR],
        int form_count)
{
        int i;
                for (i=0; i<form_count; i++)
                {
                        puts(get_form[i]);
                }
return;
}

---

I am stuck at the string_replace and process functions

I know I need to use strcat but where?



thx