#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#define __STDC_WANT_DEC_FP__
#define __STDC_VERSION__ 201112L
#include <float.h>

int main(int argc, char **argv)
{
    float flt;
    double dbl;

    if( argc != 2 ) {
        fprintf(stderr, "usage: nextfloat <number>\n");
        return 1;
    }
    flt= strtof(argv[1], NULL);
    dbl= strtod(argv[1], NULL);

    printf("single precision:\nargument == %.*g\n", FLT_DECIMAL_DIG, (double)flt);
    ++*(int32_t*)&flt;
    printf("next == %.*g\n", FLT_DECIMAL_DIG, (double)flt);

    printf("double precision:\nargument == %.*g\n", DBL_DECIMAL_DIG, dbl);
    ++*(int64_t*)&dbl;
    printf("next == %.*g\n", DBL_DECIMAL_DIG, dbl);
    return 0;
}