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Add a new file into the previous file

Hi all,
I'm now currently at the last stage of assignment where the user has to input a file name and that my program will reads this file and write it to the existing database file (will be continue from the 1st file) and then perform sort and then write it to the directory file.
Can someone lead me on how to do this? Any help will be greatly appreciated:)

this is what i have so far. I'll be having 2 files( AllCountries1.txt and AllCountries2.txt)

#include	<stdio.h>
#include 	<string.h>
#include 	<stdlib.h>
#include 	"ourhdr.h"

typedef struct				// Country Data struct declaration
    	{  	
		char code[4]; 		// Country Code 
       		char name[50];		// Country Name
		float life_expectancy;	// Life Expentancy of the Country's citizen
		int pop;		// Country's Population
    	} DATATYPE;

typedef struct				// Index Data struct declaration
	{
		char code[4];		
		long int offset;	// offset of the data
	} INDEX;

INDEX StructArray[300];	// for a lot of them
DATATYPE ActualStruct; // for a single struct

/***********************Index Copy function************************************************/

void indexCopy(INDEX* dest, INDEX src)
{
  strcpy(dest->code, src.code);
  dest->offset = src.offset;
} 

/*************************Insertion Sort function******************************************/

void sort(INDEX SortArray[], int n)
{
	int j;
	for(j=0; j < n;j++)
	{
		int k;
		INDEX temp; //Create a blank index data object
                indexCopy(&temp, SortArray[j]); //copy the data from the current line
		k = j-1;
		while (strcmp(SortArray[k].code, temp.code) >= 0 && k>=0)
		{
			indexCopy(&SortArray[k+1], SortArray[k]); //Now move them over
			k = k - 1;
		}
		indexCopy(&SortArray[k+1], temp);//And move the temp one back in
	}
} 

/*************************Print Sorted Array**********************************************/
void printsort(int size)
{
	sort(StructArray,size);	// call sort function
	int i;
	printf("Country Code     Offset\n");
	
	for (i=0; i<size; i++)
	{	
		printf("%s \t\t %u\n",StructArray[i].code, StructArray[i].offset);
	}
}

/************************Search Function by Country Code*********************************/
void search(int size)
{
	int mid, lower = 0, upper = size, flag = 1;
	INDEX cc;
	printf("Enter Country Code to search: ");
	scanf("%s", &cc);

	for(mid = (lower+upper)/2; lower <= upper; mid = (lower + upper)/2)
	{
		if(strcmp(StructArray[mid].code, cc.code) == 0)		// compare the input with the sorted array
		{
			printf("The country code is at position %d in the array at offset %u.\n", mid, StructArray[mid].offset);
			flag = 0;
			break;
		}
		if(strcmp(StructArray[mid].code, cc.code) > 0)		// compare the input with the sorted array
			upper = mid - 1;
		else
			lower = mid + 1;
	}
	
	if (flag)
		printf("Elements not found.");				// print this if the input is not in the array	
}
	

/***************************Main Function********************************************/

int main() 
{ 
	int i = 0;
	int size = 0;
	FILE *FI, *FO, *FO2;
	char Line[1000];  // NO input line (delimited by \n) is longer than 1000

	char * Tok;         // token from line
	if((FI = fopen("AC1.txt", "r")) == NULL) // open a stream from "countries"
    		err_sys("Open Fail\n");

	if((FO = fopen("DATABASE.txt", "wb")) == NULL) // open a stream from "countries"
    		err_sys("Open DATABASE Fail\n");

	if((FO2 = fopen("DIRECTORY.txt", "w+")) == NULL) // open a stream from "countries"
    		err_sys("Open DIRECTORY Fail\n");

    while ( fgets( (char *) Line,1000,FI) != NULL) // fill buffer up to newline or eof or error
    {

	Tok = strtok( Line ,",\n"); 	// skip ID number

        Tok = strtok( NULL ,",\n"); 	// this should get the country code 
        ActualStruct.code[0] = Tok[0];
        ActualStruct.code[1] = Tok[1];
        ActualStruct.code[2] = Tok[2];
        ActualStruct.code[3] = 0; 	// To create "string" 

	Tok = strtok( NULL ,",\n"); 	// this should get the country name 
        strncpy(&ActualStruct.name[0],Tok,50);	// copy string at most 50 chars

	Tok = strtok( NULL ,",\n"); 	// skip
	Tok = strtok( NULL ,",\n"); 	// skip 
	Tok = strtok( NULL ,",\n"); 	// skip
	Tok = strtok( NULL ,",\n"); 	// skip 

	Tok = strtok( NULL ,",\n"); 	// this should get the population
	ActualStruct.pop = atoi(Tok);	// convert string to integer

        Tok = strtok( NULL ,",\n"); 	// this one should get life expectancy
        ActualStruct.life_expectancy = atof(Tok);	// convert string to a floating point number

	strcpy(StructArray[i].code, ActualStruct.code);	// get the current code 
	StructArray[i].offset = ftell(FO);             	// get the current offset in the DATABASE file 

	if (fwrite(&ActualStruct, sizeof(DATATYPE),1,FO) != 1)  // write the struct to the DATABASE file 
		err_sys("fwrite error");

	i++;
	size = i;
	}

/****************************Sort the array and write into DIRECTORY*****************************/

	sort(StructArray,size);	// call sort function
	
	for (i=0; i<size; i++)
	{	
		if (fwrite(&StructArray[i], sizeof(INDEX),1,FO2) != 1)  // write the struct to the DIRECTORY file 
			err_sys("fwrite error");
	}

/*********************************************MENU************************************************/

	int c = -1;
	while( c != 4)
	{
		printf("Please select an option (1 to 4):\n");
		printf("1. Add to the DATABASE\n");
		printf("2. Search the DATABASE\n");
		printf("3. List all the countries in DATABASE by ordered Country Code\n");
		printf("4. Press q to exit\n");
		fflush(stdin);
		c = -1;		// error value if scanf fails
		scanf("%d", &c);
		switch (c)
		{
			case 1:
				break;
			case 2:
				search(size);
				break;
			case 3: 
				printsort(size);
				break;
			case 4:
				puts("Exiting program!");
				return 0;
			default:
				printf("\nNot implemented yet!");
		}
		return c;
	}

	if (fclose(FI))				// close file descriptor FI
		err_sys("Close error\n");	
	if (fclose(FO))				// close file descriptor FO
		err_sys("Close error\n");	
	if (fclose(FO2))			// close file descriptor FO2
		err_sys("Close error\n");

    	printf("------THE END------ \n");  // and this if not error :) 

}

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TommySzalapski

Make sure to close any open file before opening it differently. To add data to a file you need to open it for appending not writing like
fp=fopen("c:\\test.txt", "a")
I wouldn't try to open as "w+" and try to read and write.
I would
open as "r"
do all the reading
close the file
open as "a"
append (write) all the new data
close the file.

TommySzalapski

If you get w+ working for you, then go ahead, but I think it's easier the other way.