C++ Program Help, Numbers conversor

[easg]

Does anybody has an idea of how can I add a function to this program to display the Complement 1 and complement 2 of the inputed number?

For example the C1 and C2 of 10000001
C1 01111110
C2 01111111

// Este programa lee numeros en binario, decimal, y hex, he imprime
// en binario, decimal, y hex.

#include
#include
#include
#include
#include

// Funciones para obtener los numeros en los dif formatos
int get_binary();
int get_hex();
int get_decimal();

// Imprime los numeros en diferentes formatos
void display(int);
void display_binary(int);
void display_hex(int);
void display_decimal(int);

// Explica como funciona el programa
void help(void);

// Imprime los digitos en binario o hex
void print_binary_digit(int);
void print_hex_digit(int);

// La funcion main
void main(void)
{
char c;
int x;
int done = 0;

cout << "\nConversor de numeros\n";

// Imprime la funcion de ayuda
help();

while(!done) {

// Obtiene command
cout << "Command: ";

cout << flush;

c = getch();
cout << c << "\n";

switch(c) {
// Entrada binaria
case 'b':
cout << "Numero Binario: ";
x = get_binary();
display(x);
break;

// Entrada Hexadecimal
case 'h':
cout << "Numero Hex: ";
x = get_hex();
display(x);
break;

// Entrada decimal
case 'd':
cout << "Numero Decimal: ";
x = get_decimal();
display(x);
break;

// Ayuda
case '?':
help();
break;

// Salir
case 'q':
done = 1;
break;

// caso default - Imprime ayuda
default:
help();
break;
}
}
}


// Imprime ayuda
void help(void)
{
cout << "\nIngrese d para decimal\n"
<< " h para hex\n"
<< " b para binario\n"
<< " q para salir\n"
<< " ? para ayuda\n\n";

}

// Imprime el numero en los 3 formatos
void display(int x)
{
cout << "\n\n";
display_hex(x);
display_decimal(x);
display_binary(x);
cout << "\n";
}

// Convierte un caracter a nuemro
int ctoi(char c)
{
switch(c) {
case '0': return(0);
case '1': return(1);
case '2': return(2);
case '3': return(3);
case '4': return(4);
case '5': return(5);
case '6': return(6);
case '7': return(7);
case '8': return(8);
case '9': return(9);
case 'a':
case 'A': return(10);
case 'b':
case 'B': return(11);
case 'c':
case 'C': return(12);
case 'd':
case 'D': return(13);
case 'e':
case 'E': return(14);
case 'f':
case 'F': return(15);
default: cout << "ctoi: Caracter no numerico\n"; break;
}
}

// Obtiene un numero en binario
int get_binary(void)
{
int bin = 0;
char c;

while(1) {
cout << flush;

c = getch();

if(c == '0' || c == '1') {
cout << c;
bin = bin*2 + ctoi(c);
} else if(c == 13) {
return(bin);
}
}
}


// Obtiene un numero en decimal
int get_decimal(void)
{
int dec = 0;
char c;

while(1) {
cout << flush;

c = getch();

if(isdigit(c)) {
cout << c;
dec = dec*10 + ctoi(c);
} else if(c == 13){
return(dec);
}
}
}


// Obtiene un numero en hex
int get_hex()
{
int hex = 0;
char c;

while(1) {
cout << flush;

c = getch();

if(isxdigit(c)) {
cout << c;
hex = hex*16 + ctoi(c);
} else if(c == 13) {
return(hex);
}
}
}


// Imprime el numero en binario
void display_binary(int x)
{
int i;
int nonzero = 0;

cout << "Binary: ";

for(i = 31; i >= 0; i--) {
nonzero += (x >> i) & 1;
if(nonzero)
print_binary_digit((x >> i) & 1);
}

if(x == 0)
print_binary_digit(0);

cout << "\n";
}


// Imprime el nuemro en decimal
void display_decimal(int x)
{
cout << "Decimal: " << x << "\n";
}


// Imprime el nuemro en hex
void display_hex(int x)
{
int i;
int nonzero = 0;

cout << "Hex: ";
for(i = 7; i >= 0; i--) {
nonzero += (x >> (i * 4)) & 0xF;
if(nonzero)
print_hex_digit((x >> (i * 4)) & 0xF);
}

if(x == 0)
print_hex_digit(0);

cout << "\n";
}


// Imprime el digito en binario
void print_binary_digit(int x)
{
switch(x) {
case 0: cout << "0"; break;
case 1: cout << "1"; break;
default:
cout << "Error, print_digit accepts 0-15 only\n";
exit(-1);
break;
}
}


// Imprime el numero en hex
void print_hex_digit(int x)
{
switch(x) {
case 0: cout << "0"; break;
case 1: cout << "1"; break;
case 2: cout << "2"; break;
case 3: cout << "3"; break;
case 4: cout << "4"; break;
case 5: cout << "5"; break;
case 6: cout << "6"; break;
case 7: cout << "7"; break;
case 8: cout << "8"; break;
case 9: cout << "9"; break;
case 10: cout << "A"; break;
case 11: cout << "B"; break;
case 12: cout << "C"; break;
case 13: cout << "D"; break;
case 14: cout << "E"; break;
case 15: cout << "F"; break;
default:
cout << "Error, print_hex_digit accepts 0-15 only\n";
exit(-1);
break;
}
}

[doctorgonzo]

To get the complement of a number, XOR it with all 1s.

For an 8-bit number, that means XORing it with 255 decimal, FF hex, or 11111111 binary.

C ^ 11111111 = Complement of C

To get the two's complement, just add 1 to the complement.

(C ^ 11111111) + 1 = Two's complement.