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Read lines from file, tokenise them, save data into an array of structs.
Character Strings example from a Well House Consultants training course
More on Character Strings [link]

This example is described in the following article(s):
   • Splitting a record into individual data values in C - [link]

Source code: s4.c Module: C206
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

typedef struct {
        char tlc[4]; float lati; float longi; char placename[61]; int p2005; } Station, *Depot;

/* Combined example - reads a whole file line by line and creates a structure for each od the
lines; stores pointers to each of the lines in an array. A fairly typical example of initial
data setup. */

main () {

        Depot ourlocal[3000]; // Allow up to 3000 stations
                        // For "production" code would use calloc and realloc to make size dynamic
                        // but in this example I was keeping code a bit easier to follow
        int nstations = 0;
        Depot Current;

        FILE * datasource;
        char lynes[161];

        datasource = fopen("railstats.xyz","r");

        while (fgets(lynes,160,datasource)) {

        Current = malloc(sizeof(Station)); /* Allocate memory a station */

        int passengers[6];
        char *four_code = strtok(lynes,"\t");
        char *tlc = strtok(NULL,"\t");
        strncpy(Current->tlc,tlc,3); // Safe copy, limiting at 3 charater string
        Current->tlc[3] = '\0';

        char *postcode = strtok(NULL,"\t");
        char *osref = strtok(NULL,"\t");
        char *lati = strtok(NULL,"\t");

        char *longi = strtok(NULL,"\t");

        char *placename = strtok(NULL,"\t");
        strncpy(Current->placename, placename, 60); // Safe copy (do not use strcpy!)

        int k;
        int complete = 1;
        for (k=0; k<6; k++) {
                char *nextnum = strtok(NULL,"\t");
// Check if we really do have numbers for each year
                if (! nextnum) {
                        complete = 0;
                if (nextnum[0] < '1' || nextnum[0] > '9') {
                        complete = 0;
                passengers[k] = atoi(nextnum);

        Current->p2005 = passengers[2];

// If the record is complete, store it.
// But if it's no good, release the memory

        if (complete) {
                Current->lati = atof(lati);
                Current->longi = atof(longi);
                ourlocal[nstations++] = Current;
        } else {
                free(Current); /* Avoid memory being lost (leaked) */


// Having set the data structure up (the real purpose of this demo),
// do something to actually make use of it ;-)

        int k;
        for (k=0; k<nstations; k++) {
                Current = ourlocal[k];
                printf("%3s / %s\n",(*Current).tlc,(*Current).placename);
                printf("%3s / %s\n",Current->tlc,Current->placename); /* Same Thing! */


Learn about this subject
This module and example are covered on the following public courses:
 * Learning to Program in C
 * Learning to program in C and C++
 * Programming in C
 * C and C++ Programming
 * Learning to program in C and C++
 * C and C++ Programming
Also available on on site courses for larger groups

Books covering this topic
Yes. We have over 700 books in our library. Books covering C and C++ are listed here and when you've selected a relevant book we'll link you on to Amazon to order.

Other Examples
This example comes from our "Character Strings" training module. You'll find a description of the topic and some other closely related examples on the "Character Strings" module index page.

Full description of the source code
You can learn more about this example on the training courses listed on this page, on which you'll be given a full set of training notes.

Many other training modules are available for download (for limited use) from our download centre under an Open Training Notes License.

Other resources
• Our Solutions centre provides a number of longer technical articles.
• Our Opentalk forum archive provides a question and answer centre.
The Horse's mouth provides a daily tip or thought.
• Further resources are available via the resources centre.
• All of these resources can be searched through through our search engine
• And there's a global index here.

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