#include <stdio.h>

int main(void)
{
    double f;
    
    f = 123E12;    /* 123×10の12乗 */
    printf("%g\n", f);
    
    f = 1.23e-12;  /* 1.23×10の-12乗 */
    printf("%g\n", f);
    
    return 0;
}