Question

Write a C program, that would take a negative number as a input from the console, and convert it into 2’s complement binary representation. Recall that, there are two steps to that:

● 1’s complement of the positive bitwise representation, which is similar to bit flipping.

○ Find out the appropriate bitwise operator for that, or do it manually.

● Add 1 with the 1’s complement number.

○ Simply add 1 with the number you get in the previous step. And for this problem, assume that the number is 5 bits long. Obviously, the most significant bit is used for the sign. Sample input output are:

Input	Output
-12	10100
-9	10111
-7	11001
-16	10000

Answer 1

C Program

#include<stdio.h> // function declaration void getBinary(int, int[]); void flipBits(int[]); void addBit1(int[]); // main function int main() { int i; int number; int binary[] = {0,0,0,0,0}; printf("Enter the number: "); scanf("%d",&number); getBinary(number, binary); flipBits(binary); addBit1(binary); printf("2's complement is: "); for(i = 0; i < 5; i++) printf("%d", binary[i]); printf(" "); } // function to convert a decimal to binary and // store it into an array of integers 0,1 void getBinary(int number, int binary[]) { int index = 4; if(number < 0) number = number * -1; while(number > 0) { int r = number % 2; binary[index--] = r; number /= 2; } } // function to flip bits of the binary array void flipBits(int binary[]) { int i; for(i = 0; i < 5; i++) { if(binary[i] == 0) binary[i] = 1; else binary[i] = 0; } } // function to add binary 1 to the // array void addBit1(int binary[]) { int i; int rem = 0; // loop from back to front of the array for(i = 4; i >= 0; i--) { // extract the bit at i'th position int bit = binary[i]; // if at iteration i = 4 (at first iteration) if(i == 4) { // if bit is 1 if(bit == 1) { // make that bit to 0 binary[i] = 0; // store the remainder rem = 1; } else // else simply make the bit to 1 binary[i] = 1; } // for all other iterations else { if(bit == 1 && rem == 1) binary[i] = 0; else if(bit == 0 && rem == 1) { binary[i] = 1; rem = 0; } } } }

OUTPUT