fprintf and looping in c

Question

I successfully wrote this program that outputs a report in the terminal.

Though, when I attempt to print the same report to a disk file, I can't seem to figure out how to preserve the 'while' loop and get all the report out to print to disk file.

I've tried a couple of things like removing the 'header' function and placing that syntax in the 'summary' function along with all the necessary 'fprintf' statements in there. The outcome of this is just one line appearing in disk file output. Here is the transactiondata.txt file:

IMPORT     -25.19
EXPORT      35.41
EXPORT     100.25
IMPORT    -500.34
EXPORT     240.35
IMPORT    -134.56
EXPORT     459.56

How should I structure the code so that I get the same output that appears in the terminal window in a disk file?

The disk file output should look like this

The MoneyMaking Corporation
550 Warm Sands Drive
Palm Springs, CA 92262

Type            Amount              Net
----            ------              ---
IMPORT          -25.19            -25.19
EXPORT           35.41             10.22
EXPORT          100.25            110.47
IMPORT         -500.34           -389.97
EXPORT          240.35           -149.52
IMPORT         -134.56           -284.08
EXPORT          459.56            175.48

The net total for the month is $174.48
Transactions processed: 7

This is my code:

//C Libraries
#include <stdio.h>
#include <math.h>

//Global Variable Declarations

FILE *datafile;                  //disk file (for input)
FILE *reportfile;                // report file (for output)
char type [7];                   //Transaction Type: either IMPORT or EXPORt

float amount;                     //Transaction Amount
float absamount;                  //abs amount
float total;                      //Total
float runningsum;                 // End net balance at end of every transaction
int count;                        //Count of transactions

// Function Prototypes

void header (void);
void process (void);
void summary (void);

//*************************************************
//*************************************************
// M A I N   F U N C T I O N
//*************************************************
//*************************************************


int main (void){
// Initialize accumulating variables
    datafile = fopen("c:\\class\\mod5\\examples\\transactiondata.txt","r");   // Open input file
    count = 0;
    total = 0.00;
    runningsum = 0.00;

// Produce Report

   header();
   process();
   summary();

   fclose(datafile);
   system("pause");
   return 0;

}

// *************************************************************
// Header - prints a header on the report
// *************************************************************

void header (void)
{
    printf("The MoneyMaking Corporation\n");
    printf("550 Warm Sands Drive\n");
    printf("Palm Springs, CA 92262\n\n");

    printf("Type            Amount              Net\n");
    printf("----            ------              ---\n");
}

// *************************************************************
// Process - produces the detail lines of the report
// *************************************************************


void process (void)
{
    while(!feof(datafile))
    {
        fgets(type, 7, datafile);
        fscanf(datafile,"%f\n", &amount);
        absamount = fabs(amount);
        runningsum = amount + runningsum;
        printf("%s %15.2f %17.2f\n",type,absamount,runningsum);

    count++;              // You could also use count = count + 1
    total = total + amount;
    }


}

// *************************************************************
// Summary - prints the report summary (including accumulators)
// *************************************************************

void summary (void)
{
    // Local Variables

    float net;  //net values


    printf("\nThe net total for the month is $%1.2f\nTransactions processed: %d\n", total, count);

}

Answer 1

---

use fprintf.

void process (void)
{
    FILE *of = fopen("O_File", "a"); // reportfile the report file I guess
    while(!feof(datafile))
    {
        fgets(type, 7, datafile);
        fscanf(datafile,"%f\n", &amount);
        absamount = fabs(amount);
        runningsum = amount + runningsum;
        fprintf(of, "%s %15.2f %17.2f\n",type,absamount,runningsum);
        fprintf(stdout, "%s %15.2f %17.2f\n",type,absamount,runningsum); // to print to console

    count++;              // You could also use count = count + 1
    total = total + amount;
    }
    fclose(of);

}

---

I should have been more attentive to say the least, my above logic is pretty much an inefficient code with multiple openings, would server better if fopen and fclose calls are moved to main(). and considering FILE *reportfile is global nothing much is required except changing fprintf calls to write using reportfile instead of of.

instead of using those fprintf calls open reopen close logic

this code

int ofd = open("O_File", O_RDWR|O_APPEND);
close(1);
close(2);
dup(ofd);
close(ofd);

before calling below code sequence

// Produce Report

   header();
   process();
   summary();

should serve the purpose,

man -a dup

P.S - pretty much linux code untested on other platforms.