//以二進制的形式輸出整數
#include<stdio.h>
void?to_binary(unsigned?long?n);
int?main()
{
?unsigned?long?number;
?printf("請輸入一個整數（按q退出）：\n");
?while(scanf("%ul",&number)==1)
?{
??printf("二進制數是：");
??to_binary(number)?;
??putchar('\n');
??printf("請輸入一個整數（按q退出）：\n");
??
?}
?printf("Done.\n");
?return?0;
?}?
void?to_binary(unsigned?long?n)//遞歸函數
?{
??int?r;
??r=n%2;
??if(n>=2)
??to_binary(n/2);
??putchar('0'+r);
??}

#include?<stdio.h>
int?a[100]={-1};
int?i;
void?turn?(int?num){
????if(num){
????????a[i++]=num%2;
????????turn(num/2);
????}
}
int?main(int?argc,?const?char?*?argv[])?{
????i=0;
????int?n;
????scanf("%d",&n);
????turn(n);
????for(int?j=i-1;j>=0;j--){
????????printf("%d",a[j]);
????}
????printf("\n");
????return?0;
}

差不多的

#include?<iostream>
#include?<vector>
using?namespace?std;
vector?<int>?a;
void?turn?(int?n){
????if(n){
????????n/=2;
????????int?m=n%2;
????????a.push_back(m);
????????turn(n);
????}
}
int?main(int?argc,?const?char?*?argv[])?{
????int?x=10;
????turn(x);
????for(int?i=0;i<a.size();i++){
????????cout<<a[i];
????}
????return?0;
}

c++差不多吧。。

編寫遞歸函數將十進制數轉換成二進制數輸出。
* 算法說明：
*/
#include <iostream>
using namespace std;
void d2b( int n )
{
}
int main()
{
int a;
cin >> a; //輸入十進制數
d2b( a ); //轉換成二進制數輸出
return 0;

#include<iostream>

using namespace std;

void d2b(int n)
{
?if (n == 0)
?{
??return;
?}
?else
?{
??d2b (n / 2);

??n = n % 2;

??cout << n;
?}
}
int main()
{
?int a;

?cout<<"請輸入一個十進制數：";

?cin >> a;

?if (a == 0)
?{
??cout << 0;
?}
?else
?{
??cout << "二進制數為：";

??d2b ( a );
?}
?cout << endl;

?return 0;
}