Chapter 2, float data type

chap2>cat float1.c
#include <stdio.h>
#define DELTA 8
void printfloat(float);

main() {
    float x;
    printf("\n          Dec     Hex                  binary      \n\n");
    for (x = -DELTA; x <= DELTA; x++)
        printfloat(x);
    printf("\n");
}

void printfloat(float x) {
    unsigned long i;
    union floatandlong {
        float asfloat;
        long  aslong;
    } bits32;

    bits32.asfloat = x;
    printf(" %12.2f  %8.8x  ", bits32.asfloat, bits32.aslong);
    for (i = 0x80000000ul; i > 0; i>>=1)
        printf("%c", (i & bits32.aslong ? '1' : '0')); 
    printf("\n");
}
unix> gcc float1.c
unix> ./a.out

          Dec     Hex                  binary      

        -8.00  c1000000  11000001000000000000000000000000
        -7.00  c0e00000  11000000111000000000000000000000
        -6.00  c0c00000  11000000110000000000000000000000
        -5.00  c0a00000  11000000101000000000000000000000
        -4.00  c0800000  11000000100000000000000000000000
        -3.00  c0400000  11000000010000000000000000000000
        -2.00  c0000000  11000000000000000000000000000000
        -1.00  bf800000  10111111100000000000000000000000
         0.00  00000000  00000000000000000000000000000000
         1.00  3f800000  00111111100000000000000000000000
         2.00  40000000  01000000000000000000000000000000
         3.00  40400000  01000000010000000000000000000000
         4.00  40800000  01000000100000000000000000000000
         5.00  40a00000  01000000101000000000000000000000
         6.00  40c00000  01000000110000000000000000000000
         7.00  40e00000  01000000111000000000000000000000
         8.00  41000000  01000001000000000000000000000000

unix>