bubblesort.cpp

#include <iostream>
#include <vector>
#include <string>

using namespace std;

/* 简单版本 */
void bubblesort( vector<int> & vec )
{
    for ( int i = 0; i < vec.size() - 1; i++ )
    {
        for ( int j = 0; j < vec.size() - i - 1; j++ )
        {
            if ( vec[j] > vec[j + 1] )
            {
                swap( vec[j], vec[j + 1] );
            }
        }
    }
}


/* 改进版本 */
void bubblesort1( vector<int> & vec )
{
    for ( int i = 0; i < vec.size() - 1; i++ )
    {
        bool exchange = false;
        for ( int j = 0; j < vec.size() - i - 1; j++ )
        {
            if ( vec[j] > vec[j + 1] )
            {
                swap( vec[j], vec[j + 1] );
                exchange = true;
            }
        }

        if ( !exchange )
        {
            break;
        }
    }
}


void printvec( const vector<int> & vec, const string & strbegin = "", const string & strend = "" )
{
    cout << strbegin << endl;
    for ( auto val : vec )
    {
        cout << val << "\t";
    }

    cout << endl;
    cout << strend << endl;
}


int main( void )
{
    vector<int> vec = { 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 };
    printvec( vec );

    bubblesort1( vec );

    printvec( vec, "after sort", "" );
}