使用while循环计数数字 [英] Counting digits using while loop

问题描述

我最近制作了一个程序，需要检查用户输入的数字中的数字位数。因此，我做了以下代码：

  int x; 
 cout<< 输入数字：; 
 cin>> X; 
 x / = 10; 
 while（x> 0）
 {
 count ++; 
 x = x / 10; 
} 
  

从我可以告诉（即使有限的经验）

有没有人知道如何改进这个代码（而不是使用内置的c ++函数）？

在这个例子中，你可以读取一个字符串，

这里是对数的例子：

  #include< iostream> 
 #include< cmath> 
 
 using namespace std; 
 
 int main（）
 {
 double n; 
 cout<< 输入数字：; 
 cin>> n; 
 
 cout<< 日志10是< log10（n）<< endl; 
 cout<< 数字是< ceil（log 10（fabs（n）+1））< endl; 
 return 0; 
} 
  

I was recently making a program which needed to check the number of digits in a number inputted by the user. As a result I made the following code:

int x;    
cout << "Enter a number: ";
cin >> x;
x /= 10;
while(x > 0)
{
  count++;
  x = x/10;
}

From what I can tell (even with my limited experience) is that it seems crude and rather unelegant.

Does anyone have an idea on how to improve this code (while not using an inbuilt c++ function)?

解决方案

In your particular example you could read the number as a string and count the number of characters.

But for the general case, you can do it your way or you can use a base-10 logarithm.

Here is the logarithm example:

#include <iostream>
#include <cmath>

using namespace std;

int main()
{
    double n;
    cout << "Enter a number: ";
    cin >> n;

    cout << "Log 10 is " << log10(n) << endl;
    cout << "Digits are " << ceil(log10(fabs(n)+1)) << endl;
    return 0;
}

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