// g.cpp : 定义控制台应用程序的入口点。
//
#include "stdafx.h"
#include"stdio.h"
#include"stdlib.h"
#include"string"
#include"iostream"

using namespace std;

struct location
{
    int longitude;
    int latitude;
};
struct census
{
    string name;
    long population;
     location position;
};
census * create();
census * sort1(census *); // sort on city names;
census * sort2(census *); // sort on population;
census * sort3(census *); // sort on longtitude;
census * sort4(census *); // sort on latitude;
void display(census *, int);

int _tmain(int argc, _TCHAR* argv[])
{
    census * k = create();
    display(sort1(k), 1);
    display(sort2(k), 2);
    display(sort3(k), 3);
    display(sort4(k), 4);
    system("Pause");
    return 0;
}
census * create()
{
    static census p[5];
    string name[5] = {"Beijing","Guangzhou","Shanghai","Xi'an","Hefei"};
    long po[5] = {32000000,24000000,35000000,18400000,15200000};
    int lo[5] = {54,32,43,60,38};
    int la[5] = {210,180,138,260,208};
    for (int i = 0;i < 5;i++)
    {
        a[i].name = name[i];
        a[i].population = po[i];
        a[i].position.latitude = la[i];
        a[i].position.longitude = lo[i];
    }
    return a;
}
census * sort1(census * a)
{
    static census p[5];
    int i,j;
    census m;
    for (i = 0;i < 5;i++)
        p[i] = a[i];
    for (i = 0;i < 5;i++)
    for (j = i + 1;j < 5;j++)
        if (p[j].name < p[j - 1].name)
        {
            m = p[j];
            p[j] = p[j - 1];
            p[j - 1] = m;
        }
    return p;
}
census * sort2(census * b)
{
    static census p[5];
    int i,j;
    census m;
    for (i = 0;i < 5;i++)
        p[i] = b[i];
    for (i = 0;i < 5;i++)
    for (j = i + 1;j < 5;j++)
        if (p[j].population < p[j - 1].population)
        {
            m = p[j];
            p[j] = p[j - 1];
            p[j - 1] = m;
        }
    return p;
}
census * sort3(census * c)
{
    static census p[5];
    int i,j;
    census m;
    for (i = 0;i < 5;i++)
        p[i] = c[i];
    for (i = 0;i < 5;i++)
    for (j = i + 1;j < 5;j++)
        if (p[j].position.latitude < p[j - 1].position.latitude)
        {
            m = p[j];
            p[j] = p[j - 1];
            p[j - 1] = m;
        }
    return p;
}
census * sort4(census * d)
{
    static census p[5];
    int i,j;
    census m;
    for (i = 0;i < 5;i++)
        p[i] = d[i];
    for (i = 0;i < 5;i++)
    for (j = i + 1;j < 5;j++)
        if (p[j].position.longitude < p[j - 1].position.longitude)
        {
            m = p[j];
            p[j] = p[j - 1];
            p[j - 1] = m;
        }
    return p;
}
void display(census * p, int n)
{
    int i;
    switch (n)
    {
    case 1:
        printf("Sort the list alphabetically:\n");
        for (i = 0;i < 5;i++)
        cout<<p[i].name<<"\n";
        break;
    case 2:
        printf("Sort the list based on population:\n");
        for (i = 0;i < 5;i++)
            cout<<p[i].population<<"\n";
        break;
    case 3:
        printf("Sort the list based on northwards: ");
        for (i = 0;i < 5;i++)
            cout<<p[i].position.latitude<<"\n";
        break;
    default:
        printf("Sort the list based on westwards: ");
        for (i = 0;i < 5;i++)
            cout<<p[i].position.longitude<<"\n";
 }
}

这个是c++？？？而且你也要说以下你的是什么问题啊。

程序是干什么的，应该说清楚，有什么问题等要说明，这样别人才能帮到你的嘛。。

a[i].name = name[i];
        a[i].population = po[i];
        a[i].position.latitude = la[i];
        a[i].position.longitude = lo[i];
这一段要用联合体才能运行么？

a[i].name = name[i];
        a[i].population = po[i];
        a[i].position.latitude = la[i];
        a[i].position.longitude = lo[i];
运行的时候会出现“name”的左边必须有类/结构/联合