C Examples: File I/O

// FILE I/O EXAMPLE - C
// (c) gigabytemon
// 26/06/2020
// 2862 abc5 66cb a008 dbd9 5bf7 0dda 04f8
// e192 33e4 e689 4efb 24b9 d34f 6c2d 1ee1

/* introduction
 * ------------
 * file i/o only involves a few steps that need to be taken
 * 1) declaring the file object, i.e. what we will use to refer to the file
 * 2) opening the file, and in what mode (read, write, append, etc)
 * 3) performing operations on the file (write to, read from)
 * 4) closing the file
 *
 * it's important to know that some read operations will stop when it finds a space ( )
 * while others will only stop at the end of the line (\n)
 * also, write operations will overwrite the contents of a file unless opened explicitly
 * in append mode.
 */

#include <stdio.h>

void writingToFile() {

    //declare file object
    FILE *fp; //this is a pointer, pointing to a FILE object that we are calling fp

    //we must open the file before we can do anything
    // >> object = fopen("filename", "access mode")
    fp = fopen("C:/project_files/test.txt", "a+");

    /* access modes:
     * r = for reading only
     * w = for writing (overwrite) only (creates file if it doesnt exist)
     * a = for writing in append mode (creates file)
     * r+ = for reading and writing (overwrite)
     * w+ = for reading and writing (overwrite) (creates file)
     * a+ = for reading and writing (append mode)
     */

     //writing to file
     // >> fprintf(object, "string")
     fprintf(fp, "Wrote this string using fprintf. \n");

     // >> fputs("string") << doesn't need object reference
     fputs("Wrote this string using fputs. \n");

     //close the file after using it
     // >> fclose(object)
     fclose(fp);

}

void readingFromFile() {

    //declare file object
    FILE *fp;
    //declare a character buffer for the strings we will read from the file
    char buffer[255];

    //open the file in read mode
    fp = fopen("C:/project_files/test.txt", "r");

    //reading from file
    // >> fscanf(object, "%s", destination)
    //NOTE: THIS WILL ONLY READ UNTIL IT ENCOUNTERS A SPACE (BLANK CHARACTER)
    fscanf(fp, "%s", buffer);
    printf("Line 1: %s\n", buffer);

    // >> fgets(destination, buffer size, (FILE*)object)
    //NOTE: THIS WILL READ UNTIL END OF LINE
    fgets(buffer, 255, (FILE*)fp);
    printf("Line 2: %s\n", buffer);

    //close the file
    fclose(fp);

}

void main() {
    writingToFile();
    readingFromFile();

}