Question

// Write a function that returns 0 if x is 0, returns -1

// if x < 0, returns 1 if x > 0

// Your code must follow the Bit-Level Integer Coding Rules

// on the textbook (located between hw 2.60 and 2.61).

// You can assume w = 32.

// The only allowed operations in your code are:

// ! ~ & ^ | + << >>

// This requirement is more restrictive than the coding rules.

// You can not use if else.

int sign(int x) {

return 0;

}

Answer 1

#include <stdio.h>

int sign(int x) {

return 0 + (x >> 31) - (- x>>31);

}

int main()
{
int x;
printf("Please enter x: \n");
scanf("%d",&x);
int a = sign(x);
printf("returned value is: %d", a);
return a;
}

The logic what i wrote above for sign function is:

The shift operator converts every value which is less than 0 to -1. Every other number to 0,

When we do -x>>31 with x is positive number then it return -1.

But when we do for 0 then n>>31 and -n>>31 both returns 0.

So from above conclusion the formula that created is:

0 + (x >> 31) - (- x>>31)

Output:

1 )

Please enter x:

15

returned value is: 1

2)

Please enter x:

0

returned value is: 0

3)

Please enter x: -50

returned value is: -1