First of all I've been searching for the outcome of a negative input in an unsigned int but can't find out how it is converted. Like for example -3. How does -3 look like and how did it turn out like that?
How about subtracting from it?
What will happen?
#include <stdio.h>
int main(){
unsigned int num1 = 3, num2 = -2;
printf("num1's initial value is %u.\n",num1);
printf("num2's initial value is %u.\n",num2);
num1 = num1 + 1;
num2 = num2 - 1;
printf("num1's value is now %u.\n",num1);
printf("num2's value is now %u.\n",num2);
num1 = 2147483647;
num2 = -2147483648;
printf("num1's value is now %u.\n",num1);
printf("num2's value is now %u.\n",num2);
num1 = num1 + 1;
num2 = num2 - 1;
printf("num1's value is now %u.\n",num1);
printf("num2's value is now %u.\n",num2);
return 0;
}
Okay, Let's go line by line..
1 . unsigned int num1 = 3, num2 = -2;
for num2 = -2 ; It will show as a positive integer of value of
max unsigned integer - 1 (value depends on computer architecture and compiler).
like if you assign num2 = X (say) and the stored value will be MAX_UNSIGNED_VALUE - (X-1).
Basically It will assign the bit pattern representing -X (in 2's complement) to the unsigned int. Which will be a large unsigned value. For 32 bit ints this will be 2^32 - (X+1).
Next the line
num2 = -2147483648;
So I'm considering 32 bit int it will store the (max value of an unsigned int - 2147483647). that is
num2 = (4294967295-2147483647) = 2147483648
Very detailed explanation about how this conversion happens is given, in the following articles.
Hope this helps!