Question

我正在尝试编写一个能找到数字反转的函数，所以如果输入1234，反之则是4321。

#include <iostream>
using namespace std;

int reverse(int);

int main()
{
    cout << "This is the special difference calculator. Please enter 
positive integers: " << endl;

reverse();

}

int reverse(int num)
{
    int num, remainder, reversenum;
    cin >> num;
    while (num != 0)
    {
        remainder = num % 10;
        reversenum = reversenum * 10 + remainder;
    }
    return reversenum;
}

我也尝试在main中创建一个变量并将其设置为reverse（int），但它表明它是错误的。老实说，我不知道我在做什么，所以任何帮助都会非常感激！

Answer 1

您仍然不明白功能如何运作。你的逻辑错了（就我而言）我将其编码为2位数字。我给你留下了3,4和5位数字的数学公式。使用嵌套循环或输入操作来选择正确的方程式。阅读以下内容以了解有关功能的更多信息。 Stack Overflow不用于作业帮助，下次在寻求帮助之前更多地阅读并尝试更多代码。阅读：http://www.cplusplus.com/doc/tutorial/functions/

#include <iostream>
using namespace std;

int rev_function (int num)
{
  int r;
   //For 2 digit numbers 
  r =  (10)*(num % 10) + (num - (num % 10)) / 10 ;

//For 3 digit numbers 
//f(x) = (100)(x % 10) + ((x - (x % 10)) % 100) + (x - (x % 100)) / 100 

//For 4 digit numbers 
//f(x) = (1000)(x % 10) + ((x - (x % 10)) % 100) * 10 + ((x - (x % 100)) % 1000) / 10 + (x - (x % 1000)) / 1000 

//For 5 digit numbers 
//f(x) = (10000)(x % 10) + ((x - (x % 10)) % 100) * 100 + ((x - (x % 100)) % 1000) + ((x - (x % 1000)) % 10000) / 100 + (x - (x % 10000)) / 10000
  return r;
}

int main ()
{
  int z;
  int num;
  cout << "\nThis is the special difference calculator.";
    cout << "\n Please enter positive integers: ";
    cin >> num;
  z = rev_function (num);
  cout << "The result is " << z;
}

所以输出结果为：

This is the special difference calculator.
 Please enter positive integers: 12
The result is 21

Answer 2

您的代码中存在一些逻辑错误。请尝试以下代码（请注意评论）：

#include <iostream>
using namespace std;

int reverse();

int main()
{
    cout << "This is the special difference calculator. Please enter  positive integers: " << endl;

    reverse();

}

int reverse()
{
    int num, remainder, reversenum=0;//reversenum should be initialized to zero
    cin >> num;
    while (num != 0)
    {
        remainder = num % 10;
        num = num/10; // Add this line so that while statement works correctly
        reversenum = reversenum * 10 + remainder;
    }
    return reversenum;
}

C ++尝试从main调用函数

2 个答案: