组合的输出

 1 #include<iostream>
 2 #include<cstdio>
 3 using namespace std;
 4 
 5 const int N=25;
 6 int n,r,a[N];
 7 
 8 void solve(int l,int b){
 9     if(l>r){
10         for(int i=1;i<=r;i++)
11             printf("%3d",a[i]);
12         cout<<endl;
13     }else{
14         for(int i=b;i<=n;i++){
15                 a[l]=i;
16                 solve(l+1,i+1);
17         }
18     }
19 }
20 int main(){
21     cin>>n>>r;
22     solve(1,1);
23     return 0;
24 }