magic of C function printf() v1.c

/*
    magic of C function printf() v1.c

    Use of \b in function printf()
    to move print cursor left

    printf("\b");   // move cursor one space left (backward)

https://stackoverflow.com/questions/6792812/the-backspace-escape-character-b-unexpected-behavior

*/

#include <stdio.h>
#include <time.h>                   // for clock()

#define SHORT_TIME 25               // time for delay() in milliseconds
#define LONG_TIME 30*SHORT_TIME     // time for delay() in milliseconds

void delay(int milliseconds)
{
    clock_t start_time = clock();   // get start time

    // looping (do nothing) till required time is not acheived
    while (clock() < start_time + milliseconds)
        ;                           // do nothing
}

// move cursor howMuch spaces left
void moveCursorLeft(int howMuch)
{
    int i;

    for (i=0; i<howMuch; i++)       // repeat howMuch times
    {
        printf("\b");               // move cursor one space left
    }
}

// delete characters howMuch spaces left
void backspace(int howMuch)
{
    int i;

    for (i=0; i<howMuch; i++)       // repeat howMuch times
    {
        printf("\b \b");            // delete one left character
        delay(SHORT_TIME);          // to make process visible
    }
}

// print howMuch characters ch
void characters(char ch, int howMuch)
{
    int i;

    for (i=0; i<howMuch; i++)       // repeat howMuch times
    {
        printf("%c",ch);
        delay(SHORT_TIME);          // to make process visible
    }
}

// printing howMuch digits, cyclic from firstDigit to 9
// 0 (ascii 48), 9 (ascii 57)
void digits(int firstDigit, int howMuch)
{
    int offset=0, counter=0;
    char ch = '0' + firstDigit;     // calculate first character to print

    for (counter=0; counter<howMuch; counter++)     // repeat howMuch times
    {
        printf("%c",ch + offset);   // print character

        offset++;                   // next character

        if(ch+offset>'9')           // if we reach character '9'
        {
            offset = 0;             // to begin again
            ch = '0';               // from '0'
        }

        delay(SHORT_TIME);          // to make process visible
    }
}

// printing howMuch small letters, cyclic from ch to 'z'
// a (ascii 97), z (ascii 122)
void smallLetters(char ch, int howMuch)
{
    int offset=0, counter=0;

    for (counter=0; counter<howMuch; counter++)     // repeat howMuch times
    {
        printf("%c",ch+offset);     // print letter

        offset++;                   // next letter

        if(ch+offset>'z')           // if we reach letter z
        {
            offset=0;               // to begin again
            ch = 'a';               // from 'a'
        }

        delay(SHORT_TIME);          // to make process visible
    }
}

// printing howMuch capital letters, cyclic from ch to 'Z'
// A (ascii 65), Z (ascii 90)
void capitalLetters(char ch, int howMuch)
{
    int offset=0, counter=0;

    for (counter=0; counter<howMuch; counter++)     // repeat howMuch times
    {
        printf("%c",ch+offset);     // print letter

        offset++;                   // next letter

        if(ch+offset>'Z')           // if we reach last letter 'Z'
        {
            offset = 0;             // to begin again
            ch = 'A';               // from 'A'
        }

        delay(SHORT_TIME);          // to make process visible
    }
}

int main(void)
{
    int i, j, row_length = 52, number_of_times = 2;

    printf("\n \t \t Magic of C function printf() \n\n");

    // print ruler
    printf("\n123456789012345678901234567890123456789012345678901234567890\n");

    printf("\n\n");

    characters('*',row_length);         // row_length times printing character '*'

    printf("\n\n");

    digits(1,row_length);               // printing row_length characters, cyclic from 1 to 9

    printf("\n\n");

    smallLetters('a',row_length);       // printing row_length characters, cyclic from 'a'

    printf("\n\n");

    capitalLetters('A',row_length);     // printing row_length characters, cyclic from 'A'

    printf("\n\n\n");

    for (j=0; j<number_of_times; j++)   // do this number_of_times times
    {
        characters('*', row_length);    // printing character '*' row_length times
        delay(LONG_TIME);               // to make process visible
        backspace(row_length);          // delete characters backward

        digits(1, row_length);          // printing row_length characters, cyclic from 1 to 9, row_length times
        delay(20*SHORT_TIME);           // to make process visible
        backspace(row_length);          // delete characters backward

        smallLetters('a', row_length);  // printing row_length characters, cyclic from 'a' to 'z', row_length times
        delay(20*SHORT_TIME);           // to make process visible
        backspace(row_length);          // delete characters backward

        capitalLetters('A', row_length);// printing row_length characters, cyclic from 'A' to 'Z', row_length times
        delay(20*SHORT_TIME);           // to make process visible
        backspace(row_length);          // delete characters backward
    }

    printf("\t \t That's all Folks ! \n\n");

    return 0;
}