Question

我在下面创建的基本程序计算2个整数的最大公约数。除零和零的特定组合外，它适用于所有数字。我很确定函数“ greatComDiv（）”中的if语句出了点问题，但我无法弄清楚它到底出了什么问题。

#include<iostream>
#include<cmath>

using namespace std;

int greatComDiv(int num1, int num2)
{
//The 2 lines below convert the numbers to their absolute value in case they are negative

num1 = abs(num1);
num2 = abs(num2);

//The if statement below takes care of the case that both numbers are zero the subsequent else statement performs the normal calculations if they are both not zero.

    if( num1== 0 && num2 == 0)
    {
      cout<<"undefined"<<endl;  
    }

    else
    {
      while(num2 > 0 )
        {
        num1%num2;
        int  tempNum = num1%num2;
        num1 = num2;
        num2 = tempNum;            
        }  
       return num1;
    }
 }

int main()
{  

int numb1, numb2;

cout<<"Enter 2 numbers -->";
cin>>numb1>>numb2;

cout<<"GCD("<<numb1<<", "<<numb2<<") = "<<greatComDiv(numb1,numb2)<<endl;

}

例如，这是一个数字3和9的测试运行：

Enter 2 numbers -->3 9
GCD(3, 9) = 3

RUN SUCCESSFUL (total time: 3s)

另一个以数字100和-150进行的测试

Enter 2 numbers -->100 -150
GCD(100, -150) = 50

RUN SUCCESSFUL (total time: 3s)

这是又一个数字为0和-9的测试。

Enter 2 numbers -->0 -9
GCD(0, -9) = 9

RUN SUCCESSFUL (total time: 2s)

但是，这是当我输入0和0时发生的情况

Enter 2 numbers -->0 0
GCD(0, 0) = Undefined
-18165920

运行成功（总时间：2秒）

为什么-18165920出现在底部？它必须是if语句，因为这仅在0和0时才发生，但是我不明白我在做什么错。我将不胜感激。

Answer 1

您应该在函数上返回一些信息。在您的特殊情况下，您不需要重新调整任何内容，这一定是打印该数字的原因。同样，在只返回一些结果的函数中打印某些内容也不是一个好习惯。试试这个：

int greatComDiv(int num1, int num2)
{
//The 2 lines below convert the numbers to their absolute value in case they are negative

num1 = abs(num1);
num2 = abs(num2);

//The if statement below takes care of the case that both numbers are zero the subsequent else statement performs the normal calculations if they are both not zero.

if( num1== 0 && num2 == 0)
{
  return 0;
}

else
{
  while(num2 > 0 )
    {
    num1%num2;
    int  tempNum = num1%num2;
    num1 = num2;
    num2 = tempNum;            
    }  
   return num1;
}
}

然后在主要代码中“捕获”异常：

int main()
{  

int numb1, numb2, gcd;

cout<<"Enter 2 numbers -->";
cin>>numb1>>numb2;

gcd = greatComDiv(numb1,numb2);
if(gdc == 0) {
    cout<<"GCD("<<numb1<<", "<<numb2<<") = undefined"<<endl;
} else {
    cout<<"GCD("<<numb1<<", "<<numb2<<") = "<<gcd<<endl;
}

}

如何修复我的最大公约数代码？它适用于除零和零以外的所有数字

1 个答案: