Float has only seven significant digits in 10. If you save more than seven digits, it will be inaccurate; If it is less than seven digits, it will be accurate. In fact, float has only the top seven, sometimes only six. . . In other words, you only need to use 7-digit integers. If the integer digit is 0, then you only need the 7+ of the first decimal that is not 0, that is, the number of small trees is greater than 7 at this time, but the significant digit is still 7. . . .