#include <cstdio>
	#include <cmath>

    //Print-format a 32-bit float by exploiting exponent
    //Blog post: http://a...content-available-to-author-only...b.io/print-fp.html	
    
	void print_fp( float number, int digits ) {
	    union {
	        float d;
	        int u;
	    };
	    
	    d = number;
	
	    //deal with sign
	    bool minus = u >> 31; 
	    u = u & ~(1 << 31); 
	    
	    //calculate base-10 exponent
	    double exp = (u >> 23) - 127;
	    double exp10 = exp / log2( 10.0 );
	
	    //adjust the number 
	    u = (u & ~(0xFF << 23)) | (127 << 23);
	    double d2 = double(d) * pow( 10.0, exp10 - int(exp10) ); 
	    if( d2 >= 10.0 ) { d2 = d2 / 10.0; exp10+=1.0; }
	    if( d2 < 1.0 ) { d2 = d2 * 10.0; exp10-=1.0; }
	
	    //print sign
	    if( minus ) printf("-");
	
	    //print integer part
	    int i = int( d2 );
	    printf("%.1d.", i);
	    d2 = d2 - i;
	
	    while( digits-- ) { 
	        d2 = d2 * 10.0;
	        int i = int( d2 );
	        printf("%.1d", i);
	        d2 = d2 - i;
	    }
	
	    //print exponent part
	    printf("e%d\n", int(exp10));
	}
	
	int main() {
	
		double d;
	
	    d = 8.589973e9;
	    printf("%.10f\n", d);
	    print_fp( d , 10 );
	
	    d = 8.589974e9;
	    printf("%.10f\n", d);
	    print_fp( d , 10 );
	
	}