//* Signed vs. Unsigned variables, some binary operations and bit shifting *
#include <iostream>
#include <iomanip>
using namespace std;

int main() {
    cout << "Please enter four numbers 0..255: ";
    unsigned char bytes[4];
    for(int i=0; i<4; i++) {
        short int input;
        cin >> input; 
        bytes[i]=(unsigned char)input;
    }

    signed char chars[4]; // this "singed char" is the default "char"
    for(int i=0; i<4; i++) {
        chars[i]=bytes[i];
    }

    unsigned long int result1;
    result1 = bytes[0];
    result1 = (result1<<8) | bytes[1]; // result1 = result1*256 + bytes[1]
    result1 = (result1<<8) | bytes[2];
    result1 = (result1<<8) | bytes[3];
    
    unsigned long int result2;
    result2 = chars[0];
    result2 = (result2<<8) | chars[1];
    result2 = (result2<<8) | chars[2];
    result2 = (result2<<8) | chars[3];
    
    unsigned long int result3;
    result3 = 0xFF & chars[0];
    result3 = (result3<<8 ) | (0xFF & chars[1]);
    result3 = (result3<<8 ) | (0xFF & chars[2]);
    result3 = (result3<<8 ) | (0xFF & chars[3]);

    signed long int result4; // this is the default "long int"
    result4=(signed long int)result1;


    cout << "Bytes read: ";
    for(int i=0; i<4; i++)
        cout << setw(5) << (int)bytes[i];
    cout << endl;

    cout << "Chars read: ";
    for(int i=0; i<4; i++)
        cout << setw(5) << (int)chars[i];
    cout << endl;

    cout << "unsigned bytes in unsigned accumulation: " << setw(15) << result1 << endl;
    cout << "signed   bytes in unsigned errorous:     " << setw(15) << result2 << endl;
    cout << "signed   bytes in unsigned accumulation: " << setw(15) << result3 << endl;
    cout << "unsigned bytes in signed   accumulation: " << setw(15) << result4 << endl;

    return(0);
}