1/23/2017, C (gcc)

1/23/2017

/*Simple program showing how to read an integer and printing it to output in different formats.*/

#include "stdio.h"

int LSB(int x);
// write a function that gets an integer and a mask and returns the result  of using the mask to reset some bits to 0
int ResetBits(int a, int mask) {
  return (a & mask);
}

//converts decimal value to a string that represents the binary number
//note that decimal is already represented in binary in the memory
//all we need is an array of characters 0 and 1 that show the number in binary
int DecimalToBinary(int decimal, char *binary) {

unsigned int temp = decimal;
    int i;
    for (i=0; i<32; i++) {
    
       //ASCII code for '0' is 48 and for '1' is 49
       
       //the bit we calculate in this loop is Least Significant Bit (LSB), so the index is 31-i
       binary[31-i] = 48+ temp % 2;
       
       //dividing by 2, simply shifts the number to right and allows us to process the next bit 
       temp = temp / 2;
       }
       
    //an end is put at the end of binary string. Again this is not a number, but an array of '0's and '1's   
    binary [32] = 0;
 }

int LSB(int x)
{
    temp=b & 0x;//this number is called the mask
    temp=temp & 0x;
    a>>3;
    //& operation can be used to force some bit to zero.
    //the mask has 0 on the bit needed, has 1 for the rest. 
    //set the bit 4,5,6 to one and leave the rest unchanged. 
    //use 0 and & to force 0, use 1 and || to force 1. 
}

int main(void) 
{
   int a;

printf("Please input an integer value: ");
   scanf("%d", &a);
   printf("\nDecimal: %d\n", a);
   printf("Hex: 0x%x\n", a);
   
   char binary[33];
   DecimalToBinary(a, binary);
   printf ("Binary: %s\n", binary);
   
   
   return 0;
}


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