//p27.c -- @CopyLeft by tsaiwn@csie.nctu.edu.tw
// demo the Limition of float in C Language, again
// Floating underflow 實數虧失 !  實數絕對值太小會被當作 0
// IEEE754/854 document
//////
/* s eeeeeee efffffff gggggggg hhhhhhhh */
/* +/- 1.fffffffgggggggghhhhhhhh * 2 **(eeeeeeee - 127)   */
/*  eeeeeeee: Exponent base 2 excess 127 */
#include<stdio.h>
#define DLOOP 146
int main( ) {    int k;
    float ans = 1.0;
    for(k=1; k<= DLOOP; ++k) ans = ans/2.0;
                  /* ans = pow(2, -146);*/
    for(k=1; k<= 7; ++k){
        printf("= %12.8g\n", ans );
        ans /= 2.0;
    }
    printf("Hit RETURN key..."); 
    getchar( ); return 0;
}
/******
C:\test2> gcc p27.c
C:\test2> a.exe
= 1.1210388e-044
= 5.6051939e-045
= 2.8025969e-045
= 1.4012985e-045
=            0
=            0
=            0
Hit RETURN key...
C:\test2>
********************/