ALGO DE DECRYPTAGE DE PWD AIM

#include <iostream.h>

char * decrypt(char * PW);
int lenght(char * chaine);
int ASCII(char lettre);

int main()
{
    // ÿÿCMPBGJHHEEHCLC est un pwd coder
	cout << decrypt("ÿÿCMPBGJHHEEHCLC") << "\n\n" ;
	return 0;
}

//////////////// FONCTION /////////////////////
char * decrypt(char * password)
{
	const int longueur = lenght(password);
	
	char * PW = new char[longueur - 2];

	int i = 0;
	while(password[i]!='\0')
	{
		PW[i] = password[i+2];
		i++;
	}
	

	long a;
	int b,c,d;
	char temp;
	int compte = 0;
	char * pass_finale = new char[(lenght(PW) / 2) - 3];


	 for(a=1;a<=lenght(PW);a = a + 2)
	 {

		 c = (( a / 2) % ( 16 + 1 ) + 1);
		 b = ASCII(PW[a - 1]) - 65;
		 
		 
		if ( (c==4) || (c==9) || (c==11) || (c==14) )
		{
			if ( (b % 2) < 1 )
			{
				b = b + 1;
			}
			else
			{
				b = b - 1;
			}
		}


		if ( (c==5) || (c==10) || (c==15) || (c==16) )
		{
			if ( (b % 4) < 2 )
			{
				b = b + 2;
			}
			else
			{
				b = b - 2;
			}
		}

		if ( (c==1) || (c==6) || (c==11) || (c==12) )
		{
			if ( (b % 8) < 4 )
			{
				b = b + 4;
			}
			else
			{
				b = b - 4;
			}
		}

		if ( (c==2) || (c==7) || (c==13) || (c==16) )
		{
			if ( b < 8 )
			{
				b = b + 8;
			}
			else
			{
				b = b - 8;
			}
		}

		if ( (c==12) || (c==13) || (c==14) || (c==15) )
		{
		
			b = 15 - b;
		}

		////////////////////////////
		d = b * 16;
		b = ASCII(PW[a]) - 65;


		if ( (c==5) || (c==7) || (c==9) || (c==10) || (c==16) )
		{
			if ( (b % 2) < 1 )
			{
				b = b + 1;
			}
			else
			{
				b = b - 1;
			}
		}

		if ( (c==1) || (c==6) || (c==9) || (c==11) || (c==12) )
		{
			if ( (b % 4) < 2 )
			{
				b = b + 2;
			}
			else
			{
				b = b - 2;
			}
		}

		if ( (c==2) || (c==7) || (c==8) || (c==9) || (c==13) )
		{
			if ( (b % 8) < 4 )
			{
				b = b + 4;
			}
			else
			{
				b = b - 4;
			}
		}
		 
		if ( (c==3) || (c==12) || (c==14) )
		{
			if ( b < 8 )
			{
				b = b + 8;
			}
			else
			{
				b = b - 8;
			}
		}

		if ( (c==8) || (c==10) || (c==11) )
		{
			b = 15 - b;
		}

		compte++;
		temp = (d + b);
		pass_finale[compte - 1] = temp;
	
	 }

	return pass_finale;
}


int lenght(char * chaine)
{
	int temp = 0;
	
	while(chaine[temp]!='\0')
	{
		temp++;
	}
	
	return temp - 1;
}


int ASCII(char lettre)
{
	
	switch(lettre)
	{

	case 'A' : return 65;break;
	case 'B' : return 66;break;
	case 'C' : return 67;break;
	case 'D' : return 68;break;
	case 'E' : return 69;break;
	case 'F' : return 70;break;
	case 'G' : return 71;break;
	case 'H' : return 72;break;
	case 'I' : return 73;break;
	case 'J' : return 74;break;
	case 'K' : return 75;break;
	case 'L' : return 76;break;
	case 'M' : return 77;break;
	case 'N' : return 78;break;
	case 'O' : return 79;break;
	case 'P' : return 80;break;
	case 'Q' : return 81;break;
	case 'R' : return 82;break;
	case 'S' : return 83;break;
	case 'T' : return 84;break;
	case 'U' : return 85;break;
	case 'V' : return 86;break;
	case 'W' : return 87;break;
	case 'X' : return 88;break;
	case 'Y' : return 89;break;
	case 'Z' : return 90;break;

	}
	
}