C++ :

#include<cstdio>
#include<iostream>
#include<cstring>
using namespace std;
int a[110];
int n,m;
void so(int k){
	for(int i=a[k-1]+1;i<=n-(m-k);++i){
		a[k]=i;
		if (k==m){
			for(int j=1;j<=m;++j) printf("%3d",a[j]);
			printf("\n");
		}
		else so(k+1);
	}
}
int main(){
    cin>>n>>m;
    if (m==0) return 0;
	so(1);	
	return 0;
}

Java :

import java.util.Scanner;


public class Main {
	static int[] a;
	static boolean[] vis;
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		while(in.hasNextInt()){
			int m = in.nextInt();
			int n = in.nextInt();
			vis = new boolean[m];
			a = new int[m];
			for(int i=0;i<m;i++)
				a[m-i-1] = i+1;
			com(m,n);
		}
	}

	public static void com(int x,int y){
		if(x<y)
			return;
		if(y==0){
			print();
			return;
		}
		vis[x-1] = true;
		com(x-1,y-1);
		vis[x-1] = false;
		com(x-1,y);
	}

	public static void print() {
		for (int i = a.length - 1; i >= 0; i--)
			if (vis[i])
				System.out.printf("%3d", a[i]);
		System.out.println();
	}
}