Get the maximum value of a variable in C

Question

Is there a function in C that returns the maximum value of a variable like this (I will name the function \"maxvalue\" in example below)?

int a;
printf(\"%d\", m         


        

Answer 1

You can do it quite easily with a C11 type-generic expression:

#define maxvalue(type) _Generic(type, int: INT_MAX, \
                                      unsigned int: UINT_MAX)

It's not a function, but I think it does what you want. Here's a simple example program:

#include 
#include 

#define maxvalue(type) _Generic(type, int: INT_MAX, \
                                      unsigned int: UINT_MAX)

int main(void)
{
    int i;
    unsigned int ui;

    printf("%u\n", maxvalue(i));
    printf("%u\n", maxvalue(ui));

    return 0;
}

And its output:

$ clang -Wall -Werror -Wextra -pedantic -std=c11 example.c -o example
$ ./example 
2147483647
4294967295

My answers are larger than yours because my system has 32-bit integers. You appear to have a 16-bit machine.