C :

#include<stdio.h>
#include<string.h>
struct magnate
{

    char name[20];  //姓名

    double property;//财产，以亿元为单位。

}a[100];

void shuru(int n);
void paixu(struct magnate *p, int n);

int main()
{
    int n, k, i;
    struct magnate *p;
    p = a;
    scanf("%d%d", &n, &k);
    shuru(n);
    paixu(p, n);
    for(i=0; i<k; i++)
    {
        printf("%s %.2lf", a[i].name, a[i].property);
        if(i<k-1)
            printf("\n");
    }

}

void shuru(int n)
{
    int i;
    for(i=0; i<n; i++)
    {
        scanf("%s", a[i].name);
        scanf("%lf", &a[i].property);
    }
}

void paixu(struct magnate *p, int n)
{
    int i, j;
    double t;
    char name[20];
    for(i=0; i<n-1; i++)
    {
        for(j=0; j<n-1-i; j++)
        {
            if((p+j)->property < (p+j+1)->property)
            {
                t = (p+j)->property;
                (p+j)->property = (p+j+1)->property;
                (p+j+1)->property = t;

                strcpy(name, (p+j)->name);
                strcpy( (p+j)->name, (p+j+1)->name);
                strcpy( (p+j+1)->name, name);

            }
        }
    }

}

C++ :

#include<stdio.h>
#include<string.h>
struct magnate
{

    char name[20];  //姓名

    double property;//财产，以亿元为单位。

}a[100];

void shuru(int n);
void paixu(struct magnate *p, int n);

int main()
{
    int n, k, i;
    struct magnate *p;
    p = a;
    scanf("%d%d", &n, &k);
    shuru(n);
    paixu(p, n);
    for(i=0; i<k; i++)
    {
        printf("%s %.2lf", a[i].name, a[i].property);
        if(i<k-1)
            printf("\n");
    }

}

void shuru(int n)
{
    int i;
    for(i=0; i<n; i++)
    {
        scanf("%s", a[i].name);
        scanf("%lf", &a[i].property);
    }
}

void paixu(struct magnate *p, int n)
{
    int i, j;
    double t;
    char name[20];
    for(i=0; i<n-1; i++)
    {
        for(j=0; j<n-1-i; j++)
        {
            if((p+j)->property < (p+j+1)->property)
            {
                t = (p+j)->property;
                (p+j)->property = (p+j+1)->property;
                (p+j+1)->property = t;

                strcpy(name, (p+j)->name);
                strcpy( (p+j)->name, (p+j+1)->name);
                strcpy( (p+j+1)->name, name);

            }
        }
    }

}