Task: Stem-and-leaf plot
C++: #include <algorithm>
#include <iomanip>
#include <iostream>
#include <vector>

const int dataset[] = {
     12,127, 28, 42, 39,113, 42, 18, 44,118, 44, 37,113,124, 37, 48,127, 36,
     29, 31,125,139,131,115,105,132,104,123, 35,113,122, 42,117,119, 58,109,
     23,105, 63, 27, 44,105, 99, 41,128,121,116,125, 32, 61, 37,127, 29,113,
    121, 58,114,126, 53,114, 96, 25,109,  7, 31,141, 46, 13, 27, 43,117,116,
     27,  7, 68, 40, 31,115,124, 42,128, 52, 71,118,117, 38, 27,106, 33,117,
    116,111, 40,119, 47,105, 57,122,109,124,115, 43,120, 43, 27, 27, 18, 28,
     48,125,107,114, 34,133, 45,120, 30,127, 31,116,146
};
const int datasize = sizeof(dataset) / sizeof(dataset[0]);

int main()
{
    typedef std::pair<int,int> StemLeaf;
    std::vector<StemLeaf> stemplot;

    for (int i = 0; i < datasize; ++i)
    {
        stemplot.push_back(StemLeaf(dataset[i] / 10, dataset[i] % 10));
    }

    std::sort(stemplot.begin(), stemplot.end());  

    int lo = stemplot.front().first; 
    int hi = stemplot.back().first; 

    for (std::vector<StemLeaf>::iterator itr = stemplot.begin(); lo <= hi; ++lo)
    {
        std::cout << std::setw(2) << lo << " |"; 

        
        for ( ; itr != stemplot.end() && itr->first == lo; ++itr)
        {
            std::cout << " " << itr->second; 
        }

        std::cout << std::endl;
    }
}

Java: import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;

public class StemAndLeaf {
	private static int[] data = { 12, 127, 28, 42, 39, 113, 42, 18, 44, 118,
			44, 37, 113, 124, 37, 48, 127, 36, 29, 31, 125, 139, 131, 115, 105,
			132, 104, 123, 35, 113, 122, 42, 117, 119, 58, 109, 23, 105, 63,
			27, 44, 105, 99, 41, 128, 121, 116, 125, 32, 61, 37, 127, 29, 113,
			121, 58, 114, 126, 53, 114, 96, 25, 109, 7, 31, 141, 46, 13, 27,
			43, 117, 116, 27, 7, 68, 40, 31, 115, 124, 42, 128, 52, 71, 118,
			117, 38, 27, 106, 33, 117, 116, 111, 40, 119, 47, 105, 57, 122,
			109, 124, 115, 43, 120, 43, 27, 27, 18, 28, 48, 125, 107, 114, 34,
			133, 45, 120, 30, 127, 31, 116, 146 };
	
	public static Map<Integer, List<Integer>> createPlot(int... data){
		Map<Integer, List<Integer>> plot = new TreeMap<Integer, List<Integer>>();
		int highestStem = -1; 
		for(int datum:data){
			int leaf = datum % 10;
			int stem = datum / 10; 
			if(stem > highestStem){
				highestStem = stem;
			}
			if(plot.containsKey(stem)){
				plot.get(stem).add(leaf);
			}else{
				LinkedList<Integer> list = new LinkedList<Integer>();
				list.add(leaf);
				plot.put(stem, list);
			}
		}
		if(plot.keySet().size() < highestStem + 1  ){
			for(int i = 0; i <= highestStem; i++){
				if(!plot.containsKey(i)){
					LinkedList<Integer> list = new LinkedList<Integer>();
					plot.put(i, list);
				}
			}
		}
		return plot;
	}
	
	public static void printPlot(Map<Integer, List<Integer>> plot){
		for(Map.Entry<Integer, List<Integer>> line : plot.entrySet()){
			Collections.sort(line.getValue());
			System.out.println(line.getKey() + " | " + line.getValue());
		}
	}
	
	public static void main(String[] args){
		Map<Integer, List<Integer>> plot = createPlot(data);
		printPlot(plot);
	}
}