Maximum Value for Unsigned Int is it -1

Question

I was trying to figure out the minimum and maximum value for an unsigned data type. I know that the minimum unsigned value is 0 and the maximum value is (2^n)-1. However, when I tried to run my program (I cannot post my code, but you can refer to this), I keep getting -1 as the maximum value. Can someone explain to me why? Also, UINT_MAX is giving me 4294967295 while ULLONG_MAX is 4294967295. However, the maximum value of unsigned int is supposed to be 65535 while unsigned long long int is supposed to be +18,446,744,073,709,551,615.Why is it the output is different?

UINT_MAX is the same bit-wise as -1 in two's complement notation. You're probably printing it out as a signed integer. — Christian Gibbons, Jan 23 '18 at 19:05

sameer chaudhari · Accepted Answer · 2018-01-23T19:32:24.913

6

Whats the format specifier are you using to print those values ? These kind of error mostly occur due to wrong format specifier.

#include <stdio.h>
#include <limits.h>

int main()
{  
    printf("%u", UINT_MAX); // This will print 4294967295 (system dependent)
    printf("%d", UINT_MAX); // This will print -1
    return 0;
}

edited Jan 23 '18 at 19:32

answered Jan 23 '18 at 19:26

sameer chaudhari

928
7
14

2

`printf("%d", UINT_MAX); // This will print -1` This is also system dependent as not every system is two's complement. – Christian Gibbons Jan 23 '18 at 19:33
2

@ChristianGibbons: While in theory non-twos-complement machines can exist, you won't find one outside a museum. – Chris Dodd Jan 23 '18 at 19:42
1

I agree with both of your comment – sameer chaudhari Jan 23 '18 at 19:43
the `%d` ver is undefined behaviour so could print anything , or format your hard drive – M.M Jan 23 '18 at 23:46
My classmates are also getting -1 – eLg Jan 23 '18 at 23:48

Maximum Value for Unsigned Int is it -1

1 Answers1