#include <stdio.h>
#include <math.h>
#include <stdlib.h>

/* given 8 bits of 0 or 1 on the command line, will interpret them in unsigned, signed, one's compliment, two's complement and excess 128 */

int
bits_unsigned (char **bits)//working
{
 int currentval; //the current value
 int currentpower; //the current power of 2
 int bitsplace; //holds the position where we are in the bits array
 int bitval; //either 0 or 1

 currentval = 0;

 for (bitsplace = 8, currentpower = 0 ; bitsplace >= 1; bitsplace--, currentpower++)
   {
     bitval = atoi(bits[bitsplace]);
     currentval = (currentval + (bitval * pow(2,currentpower)));
   }

 return currentval;
}

int
bits_signed (char **bits) //working
{
 int currentval; //the current value
 int currentpower; //the current power of 2
 int bitsplace; //holds the position where we are in the bits array
 int bitval; //either 0 or 1

 currentval = 0;

 for (bitsplace = 8, currentpower = 0 ; bitsplace >= 2; bitsplace--, currentpower++)
   {
     bitval = atoi(bits[bitsplace]);
     currentval = (currentval + (bitval * pow(2,currentpower)));
   }

 if (atoi(bits[1]) == 1) //if it is signed to be nevative
   currentval = (currentval * -1);

 return currentval;
}

int
bits_unsigned_2 (char *bits) //given an array NOT from the command line
{
 int currentval; //the current value
 int currentpower; //the current power of 2
 int bitsplace; //holds the position where we are in the bits array
 int bitval; //either 0 or 1

 currentval = 0;

 for (bitsplace = 7, currentpower = 0 ; bitsplace >= 0; bitsplace--, currentpower++)
   {
     bitval = bits[bitsplace];
     currentval = (currentval + (bitval * pow(2,currentpower)));
   }

 return currentval;
}

int
bits_ones_complement (char **bits)
{
 char newbits[8] = {0}; //creates a new array of character strings
 int bitsplace; //holds the value in bits
 int currentval; //

 if (atoi(bits[1]) == 0)
   currentval = bits_signed(bits);
 else 
   {   
     for (bitsplace = 8; bitsplace >= 1; bitsplace--)
       if (atoi(bits[bitsplace]) == 0)
         newbits[bitsplace - 1] = 1;
     currentval = (bits_unsigned_2(newbits) * -1);
   }

 return currentval;
}

int
bits_twos_complement (char **bits)
{
char newbits[8] = {0}; //creates a new array of character strings
 int bitsplace; //holds the value in bits
 int currentval; //

 if (atoi(bits[1]) == 0)
   currentval = bits_signed(bits);
 else 
   {   
     for (bitsplace = 8; bitsplace >= 1; bitsplace--)
       if (atoi(bits[bitsplace]) == 0)
         newbits[bitsplace - 1] = 1;
     if (newbits[8] == 0)
       newbits[8] = 1;
     else 
       newbits[8] = 0;
     currentval = (bits_unsigned_2(newbits) * -1);
   }

 return currentval;
}

int
bits_excess_128 (char **bits) //working
{
 int currentval;

 currentval = (bits_unsigned(bits) - 128);

 return currentval;
}

int
main (int count, char **bits)
{

 printf("Unsigned: %d\n", bits_unsigned(bits));
 printf("Signed magnitude: %d\n", bits_signed(bits));
 printf("One's complement: %d\n", bits_ones_complement(bits));
 printf("Two's complement: %d\n", bits_twos_complement(bits));
 printf("Excess 128: %d\n", bits_excess_128(bits));

 return 0;
}