Pregatire 19 Nov, Read and Write a binary structure

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

#define MAX_LINE_LEN 10000
#define MAX_NO_LINES 100

/*
 * On success, the function returns str.
If the end-of-file is encountered while attempting to read a character, the eof indicator is set (feof).
 If this happens before any characters could be read, the pointer returned is a null pointer (and the contents of str remain unchanged).
If a read error occurs, the error indicator (ferror) is set and a null pointer is also returned (but the contents pointed by str may have changed).
 *
 */

/*
 * void* malloc (size_t size);
 *
 *
 */


typedef struct{
    char first_chars[100];
    int line_length;
    int no_characters;
}LineInfo;

int main() {
    FILE * f = fopen("../in.txt", "r");
    if (f == NULL)
        return 100;

    char **tab = (char **)malloc(sizeof(char*)*MAX_NO_LINES);
    char* linie = (char *)malloc(sizeof(char)* MAX_LINE_LEN);
    char* ok=linie;
    int n = 0;
    while (ok == linie){
        ok = fgets(linie, MAX_LINE_LEN, f);
        if(ok != linie)
            break;
        tab[n] = (char*)malloc(sizeof(char) * (strlen(linie) + 1));
        strcpy(tab[n], linie);
        n++;
    }
    free(linie);
    fclose(f);
    //**************************************************  AICI AM CONTINUTUL IN MEMORIE ************//

    FILE * fout = fopen("../out.txt", "wb");
    if (fout == NULL)
        return 110;

    for(int i=0;i<n;i++){
        //Sa numaram spatiile
        int nr_spatii = 0;
        for(int j = 0; j < strlen(tab[i]);j++){
            int is_whitespace = tab[i][j] == ' ' || tab[i][j] == '\n' || tab[i][j] == '\r';
            if(!is_whitespace)
                nr_spatii++;
        }
        LineInfo li;
        li.line_length = strlen(tab[i]);
        li.no_characters = nr_spatii;
        memset(li.first_chars, 0, 100);
        strncpy(li.first_chars, tab[i], 99);
        fwrite(&li, sizeof(LineInfo), 1, fout);
//        fprintf(fout,"Number of non-spaces: %-6d : %s", nr_spatii, tab[i]);  <-- Here I am outputing variable length text.
    }
    fclose(fout);

    //!!!!!!!!!!!!!!!!!
    // I have n lines. So in the file I will have n structures.

    FILE * fin = fopen("../out.txt", "rb");
    if (fin == NULL)
        return 110;

    LineInfo *linfo = (LineInfo*)malloc(sizeof(LineInfo) * n);
    fread(linfo, sizeof(LineInfo), n, fin);
    for(int i=0; i<n;i++){
        printf("Read from file: %d : %d %s\n", linfo[i].no_characters, linfo[i].line_length, linfo[i].first_chars);
    }



    for(int i=0;i<n;i++){
        free(tab[i]);
    }
    free(tab);

    return 0;
}