求最大公因數遞迴

[popo4231 (小泰)]

#include<iostream>
using namespace std;
void swap(int* a,int* b)//若a<b則對調a與b
{
   int temp;
   if(*a<*b)
   {
      temp=*a;
      *a=*b;
      *b=temp;
   }
}
int GCD(int a,int b)
{
   int r;//貯存餘數
   r=a%b;
   if(r==0)
   {
      return b;
   }
   else
   {
      cout<<r<<endl;//印出計算過程
      for(int i=1;i<=100000000;i++);//delay空迴圈
      GCD(b,r);
   }
}
int main()
{
   int a,b,gcd;//求出gcd=(a,b)

   cout<<"求最大公因數"<<endl;
   cout<<"請輸入兩個整數"<<endl;
   cin>>a>>b;
   swap(&a,&b);
   gcd=GCD(a,b);
   cout<<"(a,b)="<<gcd<<endl;

   system("pause");
   return 0;
}
只要不能整除的都會出錯
請問哪邊錯了

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推 timrau:因為沒有return GCD(b,r)
推 ric2k1:嗯, please pay attention to the compilation warning...
→ ric2k1:main6.cpp:27: warning: control reaches end of non-void
→ ric2k1:function
→ ric2k1:("main6.cpp" is the filename I used to test...)
推 ijb:這不會是老師給同學的加分題吧...結果被饒神秒殺