Hello, World!

/*
    Hello, World!
    -by Renz Justine L. Villegas
    October 15, 2021

    Created using:                      Tested using:
    Visual Studio Code (LINUX)          Visual Studio Code
                                        www.onlinegdb.com
                                        www.programiz.com

*/

#include <stdio.h>


int msgArrCnt;
//makes the character uppercase
char upprCase(char chr){
    //if the character decimal value was 97 and above
    if (chr >= 97)
        chr = chr - 32;     //subtract 32 to match the decimal value of uppercase value in ASCII
    return chr;

}

//get the length of string
int strLength(char* chr){
    int i = 0;
    //count until the char[i] value is null
    while (chr[i] != '\0')
        i++;
    return i;
}

// (wala bang exponent function [^] sa C? Sorry nasanay sa Python at Java) exponent function
int powerOf(int base, int exp){
    int fnl = 1;
    //repeatedly multiply the base with itself in [exp value] times
    int i;
    for (i = 0; i < exp;i++)
        fnl *= base;    // Ex: base = 2; exp = 3 : 2*2*2
    return fnl;         //                       = 8
}

// convert hex letters [A,B,C,D,E,F] into its decimal value [10,11,12,13,14,15,16]
int hexLettertoInt(char letter){
    //make the character uppercase, to be ok
    int r = upprCase(letter);

    //if the letter is 'A' = 10, 'B' = 11, 'C' = 12, 'D' = 13, 'E' = 14, and 'F' = 15
    return r - 55;      // Ex: 'A' in Hex = 65 ::  65 - 55 == 10

}


int hexConvToInt(char* str){
    // store the fnl variable
    int fnl = 0;
    // get the length of the string
    int length = strLength(str);
    // loop until the value of length
    int i;
    for (i = 0; i < length ; i++){
        int curr = 0;
        int crrIndx = length - i - 1;
        // hex numbers are only 0 - 9, and the rest are A - F
        if(str[i] >= '0' && str[i] <= '9'){
            curr = str[i] - '0';        // ALWAYS REMOVE THE EMPTY CHAR to convert it into an integer

        } else {
            curr = hexLettertoInt(str[i]);
        }
        fnl = fnl + (curr*powerOf(16,crrIndx));
    }
    return fnl;
}


void strRvrs(char *str)
{
    if (*str == '\0') // avoid empty char
        return;


    char *srtg ;
    char *endg ;

            // get the value of str from the memory then make it the starting point
    for (   srtg = str,
            // end point from the memory [add the length and the loc of start then subtract 1 to remove empty char]
            endg = strLength(str) - 1 + srtg;
            // loop until the start val and end val have met
            srtg < endg;
            // [increment] Ex: 0x7ffcbcb46de1 >> 0x7ffcbcb46de2
            *srtg++,
            // [decrement] Ex: 0x7ffcbcb46dec >> 0x7ffcbcb46ded
            *endg--)
    {
        // REVERSAL PROCESS
        char tmp = *srtg;
        *srtg = *endg;
        *endg = tmp;

        //printf("%p %p\n", srtg, endg); Out: 0x7ffcbcb46de1 0x7ffcbcb46ded

    }
}



int main(){
    /*
         _   _   _____   _       _        ___     __        __   ___    ____    _       ____
        | | | | | ____| | |     | |      / _ \    \ \      / /  / _ \  |  _ \  | |     |  _ \
        | |_| | |  _|   | |     | |     | | | |    \ \ /\ / /  | | | | | |_) | | |     | | | |
        |  _  | | |___  | |___  | |___  | |_| |     \ V  V /   | |_| | |  _ <  | |___  | |_| |
        |_| |_| |_____| |_____| |_____|  \___/       \_/\_/     \___/  |_| \_\ |_____| |____/   by Renz.


        using this code you can generate Hello, World!
                    ||
                   _||_
                   \  /
                    \/                                      */
    char code[] = "1422x6c76f7266x502c6f2c5x56c64x862x4";
    int length = strLength(code);




    // ASCII CHAR:  "H  e   l   l   o   ,     W  o   r   l   d   ! "
    // HEXADECIMAL: "48 65  6c  6c  6f  2c 20 57 6f  72  6c  64  21";
    // DECIMAL:     "72 101 108 108 111 44 32 87 111 114 108 100 33"
    // 48656c6c6f2c20576f726c6421   >>  NORMAL

    // Decoding the code:
    // First, the we should reverse the code

    strRvrs(code);
    // ANS: 4x268x46c65x5c2f6c205x6627f67c6x2241
    //printf("%s \n",code);

    // Second, identify if there are 'x' char inside followed by an number,
    // remove the chars 'xn' where n is the number then reverse next n numbers.
    // Ex: ..x46c65.. == ..56c6..
    char newCode[length];
    int x, y, newLen;

    while (x < length){
        if (code[x] == 'x' && code[x+1] >= '1' && code[x+1] <= '9'){
            int revLen = code[x+1] - '0';

            //printf("::%i", revLen);
            int y;
            for (y = revLen + x + 1; y > x + 1; y--){
                // just making sure if the curr index is zero, to avoid random objects to be taken
                if (x == 0)
                    // im a bit lazy now but this code will do the job copying each char in the newCode
                    sprintf(newCode, "%c", code[x]);
                else
                    sprintf(newCode, "%s%c", newCode, code[y]);
                /* printf("%c.\n",code[i]); */
                // counting the new length of the newCode
                newLen++;
            }
            //printf("%c%c-\n", code[x], code[x+1]);
            x = revLen + x + 2;
            continue;

        } else {
            // just making sure if the curr index is zero, to avoid random objects to be taken
            // copy the new code
            if (x == 0)
                sprintf(newCode, "%c", code[x]);
            else
                sprintf(newCode, "%s%c", newCode, code[x]);
            // counting the new length of the newCode
            newLen++;

        }

        x++;
    }
    // ANS: 48656c6c6f2c20576f726c6421
    //printf("---%s---", newCode);
    //printf("%s \n",code);

    int arrSize = length/ 2;
    char tmp[64];
    int tmpInt = 0;
    int strIndx = 0;
    int strCnt = 0;
    int tmpIntArr[arrSize];

    // Let's start

    int i = -1;
    while (i <= newLen){
        tmp[strCnt-1] = newCode[i];
        if (strCnt == 2){
            tmpInt = hexConvToInt(tmp);
            tmpIntArr[strCnt] = tmpInt;
            printf("%c", tmpInt);
            //printf("%c %i %i %i\n", tmpInt , tmpInt, strCnt,i/2);

            strIndx++;
            strCnt = 0;
        }

        i++;
        strCnt++;
    }
    //printf("\n"); TEKA LANG DI KO ALAM KUNG NEED NG NEWLINE


    /*
    OUTPUT:

       ooooo ooooo ooooooooooo ooooo       ooooo         ooooooo
        888   888   888    88   888         888        o888   888o
        888ooo888   888ooo8     888         888        888     888
        888   888   888    oo   888      o  888      o 888o   o888  ooo
       o888o o888o o888ooo8888 o888ooooo88 o888ooooo88   88ooo88    888
                                                                  o88

       oooo     oooo   ooooooo   oooooooooo  ooooo       ooooooooo     oo
        88   88  88  o888   888o  888    888  888         888    88o  8888
         88 888 88   888     888  888oooo88   888         888    888  8888
          888 888    888o   o888  888  88o    888      o  888    888   88
           8   8       88ooo88   o888o  88o8 o888ooooo88 o888ooo88     oo

    */
}