Question

This is the text input for my c program.

2010161 5 
        123 1a  876 2a  654 5d  751 3b  431 2b
3000177 4
        817 2c  123 1a  555 5e  864 5d
1000007 4
        645 7a  643 6f  645 7a  123 1a
2010101 1
        431 2b
1232343 5
        643 6f  751 3b  234 2a  256 4b  654 4c
1856512 7
        555 4f  715 3g  732 2f  914 8g  754 6h  759 2h  723 1g

The meaning of text input is shown as below:

customer_no total_number_of_items_for_this_customer

item_no [row][column]    item_no [row][column]      item_no [row][column]      item_no [row][column]

Based on text input above which all will be copy into text file, in my C program, how should I write my scanf in my main function in order to successfully read information from text input above to my struct function listed below?

typedef struct{
   int buyer_id;
   int no_of_items;
   itemsinfo_t order[MAXORDER];
}buyer_t;   

typedef struct{
   int           item_no;
   int           row;
   char column;  
}itemsinfo_t;

*MAXORDER is stated as value 10, meaning that each customer only able purchase 10 maximum items.

*scanf function should able to read up to 100 customers if another text input with identical format is used in future.

Answer 1

#include <unistd.h>
#include <stdio.h>
#include <dirent.h>
#include <string.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <time.h>

#define MAXORDER 10

typedef struct{
    int            item_no;
    int            row;
    char         column;  
}itemsinfo_t;

typedef struct{          
    int buyer_id;
    int no_of_items;
    itemsinfo_t   order[MAXORDER];
}buyer_t;

void print(buyer_t*, int);
int main(int argc, char *argv[])
{
   char filename[200];
   char discard;
   buyer_t buyer[100]; // create array of 100 buyer_t
   int index = 0; // count number of buyers
   FILE *file = NULL;
   int j;
   printf("Enter file name to read buyer data: ");
   scanf("%s", filename);
        file = fopen(filename, "r");// open file
        if (file == NULL) {
                printf("Can't read file.\n");
                exit(0);
        }

        while (!feof (file)) {
                fscanf (file, "%d %d", &buyer[index].buyer_id, &buyer[index].no_of_items);// use fscanf to read data from file
       for (j = 0; j < buyer[index].no_of_items; j++) {
           fscanf(file, "%d %d %c", &buyer[index].order[j].item_no, // read all items from file
               &buyer[index].order[j].row, &buyer[index].order[j].column);
       }
       index++;
       fscanf(file, "%c", &discard); // discard newline char
   }
          
        fclose (file);// close the file;
   print(buyer, index - 1);
}

void print(buyer_t* buyer, int index)
{
   int i = 0, j;
   for (; i < index; i++) {
       printf("buyer_id: %d\nno_of_item: %d\n", buyer[i].buyer_id, buyer[i].no_of_items);// print buyers information
       for (j = 0; j < buyer[i].no_of_items; j++)// print all items
           printf("%d %d %c ", buyer[i].order[j].item_no,
                                buyer[i].order[j].row, buyer[i].order[j].column);
       printf("\n");
   }
}

sanjiv@sanjiv-VirtualBox: $ sanjiv@sanjiv-VirtualBox:-$ sanjiv@sanjiv-VirtualBox: $ gcc item.c -o item sanjiv@sanjiv-VirtualBox:-$ ./item Enter file name to read buyer data: data1.txt buyer_id: 2010161 no of item: 5 123 1 a 876 2 a 654 5 d 751 3 b 431 2 b buyer id: 3000177 no of item: 4 817 2 c 123 1 a 555 5 e 864 5d buyerid: 1000007 no of item:4 645 7 a 643 6 f 645 7 a 123 1 a buyerid: 2010101 no of item: 1 431 2 b buyer_id: 1232343 no of ite: 5 643 6 f 751 3 b 234 2 a 256 4 b 654 4 c buyer_id: 1856512 no of item: 7 555 4 f 715 3 g 732 2 f 914 8 q 754 6 h 759 2 h 723 1 q sanjiv@sanjiv-VirtualBox:-$ sanjiv@sanjiv-VirtualBox:$ sanjiv@sanjiv-VirtualBox:$ saniiv@saniiy-VirtualBox: S