#include <stdio.h>

int main(void) {
    double d = 4/7.0;

    // prints in decimal with (default) 6 decimal places
    printf("%lf\n", d);        // prints 0.571429

    // prints in scientific notation
    printf("%le\n", d);       // prints 5.714286e-01

    // picks best of decimal and scientific notation
    printf("%lg\n", d);       // prints 0.571429

    //  prints in decimal with 9 decimal places
    printf("%.9lf\n", d);    // prints 0.571428571

    //  prints in decimal with 1 decimal place and field width of 10
    printf("%10.1lf\n", d);  // prints        0.6

    //  prints in decimal with 1 decimal place and field width of 10 padded to 0's
    printf("%010.1lf\n", d);  // prints  00000000.6

    d = 1/2;
    
    // what will this print?
    printf("%lf\n",d);
    
    return 0;
}