CHANGEMENT DE BASES (2 À 36)

#include <iostream.h>
#include <conio.h>
#include <stdlib.h>

void Base(const char *nombre, const int base1, const int base2)
{
	int ascii, i, j = 0, len = 0 ;
	long d = 1, e = 0 ;
	char *res, c ;
	if((res = (char *) malloc(sizeof(char)))==NULL)
	{
		cerr << " Allocation memoire impossible !" ;
		exit(1) ;
	}


	while(nombre[len+1]!='\0')
	{
		len++ ;
	}

	// Conversion de base1 en base 10
	for(i=len;i>=0;i--)
	{
		ascii = nombre[i];

		if((ascii<48)||(ascii>122))
		{
			cout << "Caractere inconnu." ;
			getch() ;
			exit(2) ;
		}
		else if(ascii>=97)
		{
			ascii = ascii - 87 ;
		}
		else if(ascii>=65)
		{
			ascii = ascii - 55 ;
		}
		else
		{
			ascii = ascii - 48 ;
		}

		e = e + (ascii * d) ;
		d = d * base1 ;
	}


	// Conversion de base 10 en base2
	while(e!=0)
	{
		d = e % base2 ;
		e = (e - d)/base2 ;
		if(d>9)
		{
			ascii = 55 + d ;
		}
		else
		{
			ascii = 48 + d ;
		}
		res[j] = char(ascii) ;
		j++ ;
		if((res = (char *) realloc(res, j*sizeof(char)))==NULL)
		{
			cerr << "Agrandissement du bloc impossible" ;
			exit(3) ;
		}
	}
	res[j] = '\0' ;

	for(i=0;i<=(j-1)/2;i++)
	{
		c = res[i] ;
		res[i] = res[j-i-1] ;
		res[j-i-1] = c ;
	}

	cout << res ;
}


void main()
{
	clrscr() ;
	int b1, b2 , buffer=0, i=0 ;
	char *m ;
	if((m = (char *) malloc(sizeof(char)))==NULL)
	{
		cerr << " Allocation memoire impossible !" ;
		exit(4) ;
	}

	cout << "Base de 2 a 36\n\nNombre a convertir ?\n" ;
	while(buffer!=13)
	{
		if((m = (char *) realloc(m, (i+1)*sizeof(char)))==NULL)
		{
			cerr << "Agrandissement du bloc impossible" ;
			exit(5) ;
		}
		buffer = getche() ;
		m[i] = char(buffer) ;
		i++ ;
	}
	m[i-1] = '\0' ;
	while(getchar()!='\n') ;

	cout << "Base de depart ?\n" ;
	cin >> b1 ;
	cout << "Base d\'arrivee ?\n" ;
	cin >> b2 ;


	cout << "\n\t" << m << " (" << b1 << ")  -->  " ;
	Base(m, b1, b2) ;
	cout << " (" << b2 << ")\n" ;


	getch();
}