How to know if a binary integral number represents a negative number?
Date : March 29 2020, 07:55 AM
I think the issue was by ths following , It depends on the representation, of course. In two's complement, which is widely used, you simply look at the most significant bit.

Concatenating a negative number to binary number
Tag : c , By : Kristian Hofslaeter
Date : March 29 2020, 07:55 AM
hope this fix your issue 7 is probably a 32bit negative number  that is, 0xfffffff9. You need to mask it if you only want to use 9 bits: num = (num << 9)  (7 & 0x1ff)

Binary Multiplication  Negative number X Negative number
Tag : math , By : Moe Skeeto
Date : March 29 2020, 07:55 AM
With these it helps Negative integers are usually stored in 2's complement representation, which means that as an mbit number x is stored as 2mx. This is where the name two's complement comes from: adding x results in a complete power of two. Assuming we use 32 bits, 3 is stored as 2323 = 4294967293. 11111111111111111111111111111101×11111111111111111111111111111101 =
1111111111111111111111111111101000000000000000000000000000001001
(32 msb) (32 lsb)

convert negative decimal number to binary number
Date : March 29 2020, 07:55 AM
this will help decimal and int b[s] not initialized. By not initializing decimal to 0, it might have the value of 0 on a machine one day and quite different results otherwise. void decTobin(int dec, int s) {
// while loop does not set all `b`,but following for loop uses all `b`
// int b[s], i = 0;
int b[s] = { 0 }; // or int b[s]; memset(b, 0, sizeof b);
int i = 0;
}
void ndecTobin(int dec, int s) {
int b[s], i = 0, a[s], decimal, decimalvalue = 0, g;
decimal = 0;
...
decimal += decimalvalue;
}
void decTobin(unsigned number, unsigned width) {
int digit[width];
for (unsigned i = width; i > 0; ) {
digit[i] = number % 2;
number /= 2;
}
printf("%u ", number); // assume this is for debug
for (unsigned i = 0; i<width; i++) {
printf("%u", digit[i]);
}
}

How to know if it is either a positive/negative number or it is referring to a number in binary?
Date : March 29 2020, 07:55 AM

