c ++输出太多次

Question

我正在编写一个程序，输出一个递增的整数，直到达到400。即使添加的“ while”少于400 in，它也总是经过一次。有任何建议可以解决吗？

cout << "enter population of US at end of last year (in millions): ";
cin >> USpop;



do {
    USpop = USpop * 1.01007;
    year = year +1;
    cout<< "  " << year  << "  " << setprecision(1) << fixed << USpop <<endl;

} while (USpop < 400);

Answer 1

也许是这样吗？

while((USpop *= 1.01007) < 400)
{
    year = year + 1;
    cout << "  " << year << "  " << fixed << USpop << endl;
}