maximum value of int

Question

Is there any code to find the maximum value of integer  accordingly to the compiler  in C C   like Integer MaxValue function in java

User · Answer

I know it s an old question but maybe someone can use this solution   int size   0     Fill all bits with zero  0  size    size     Negate all bits  thus all bits are set to one  1    So far we have -1 as result  till size is a signed int   size    unsigned int size  gt  gt  1     Shift the bits of size one position to the right    As Standard says  bits that are shifted in are 1 if variable is signed and negative and 0 if variable would be unsigned or signed and positive   As size is signed and negative we would shift in sign bit which is 1  which is not helping much  so we cast to unsigned int  forcing to shift in 0 instead  setting the sign bit to 0 while letting all other bits remain 1   cout  lt  lt  size  lt  lt  endl     Prints out size which is now set to maximum positive value    We could also use a mask and xor but then we had to know the exact bitsize of the variable  With shifting in bits front  we don t have to know at any time how many bits the int has on machine or compiler nor need we include extra libraries

User · Answer

include  lt climits gt   include  lt iostream gt  using namespace std   int main       cout  lt  lt  INT MAX  lt  lt  endl

User · Answer

In C      include  lt limits gt    then use  int imin   std  numeric limits lt int gt   min       minimum value int imax   std  numeric limits lt int gt   max      std  numeric limits is a template type which can be instantiated with other types   float fmin   std  numeric limits lt float gt   min       minimum positive value float fmax   std  numeric limits lt float gt   max        In C    include  lt limits h gt    then use  int imin   INT MIN     minimum value int imax   INT MAX    or   include  lt float h gt   float fmin   FLT MIN      minimum positive value double dmin   DBL MIN     minimum positive value  float fmax   FLT MAX  double dmax   DBL MAX

User · Answer

Here is a macro I use to get the maximum value for signed integers  which is independent of the size of the signed integer type used  and for which gcc -Woverflow won t complain   define SIGNED MAX x     -1  lt  lt   sizeof x    8 - 1     int a   SIGNED MAX a   long b   SIGNED MAX b   char c   SIGNED MAX c      if char is signed for this target    short d   SIGNED MAX d   long long e   SIGNED MAX e

User · Answer

O K  I neither have rep to comment on previous answer  of Philippe De Muyter  nor raise it s score  hence a new example using his define for SIGNED MAX trivially extended for unsigned types      We can use it to define limits based on actual compiler built-in types also    define INT MAX   SIGNED MAX int     based on the above  we can extend it for unsigned types also   define UNSIGNED MAX x      SIGNED MAX x  lt  lt 1    1      We reuse SIGNED MAX  define UINT MAX  UNSIGNED MAX unsigned int     on ARM  4294967295    then we can have  unsigned int width   UINT MAX    Unlike using this or that header  here we use the real type from the compiler

User · Answer

include  lt iostrema gt   int main        int32 t maxSigned   -1U  gt  gt  1      cout  lt  lt  maxSigned  lt  lt    n       return 0      It might be architecture dependent but it does work at least in my setup

User · Answer

What about  1  lt  lt   8 sizeof int -2   - 1    1  lt  lt   8 sizeof int -2    This is the same as 2  8 sizeof int -2  - 1   2  8 sizeof int -2    If sizeof int    4    gt   2  8 4-2  - 1   2  8 4-2      2 30 - 1   20 30      2 32  2 - 1  max signed int of 4 bytes    You can t use 2  1  lt  lt   8 sizeof int -2   - 1 because it will overflow  but  1  lt  lt   8 sizeof int -2   - 1    1  lt  lt   8 sizeof int -2   works

User · Answer

Why not write a piece of code like   int  max neg     1  lt  lt  31   int  all ones   -1  int max pos   all ones  amp  max neg

[c++] maximum value of int

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