程序代码：

#include  <stdio.h>
#include  <stdlib.h>
#define   MAX  50
#define   SAVE_FAC(fact, exp) { if (exp > 0)                \
                                        fac[count] = fact, \
                                        exps[count++]  = i;    \
                                 }
int main()
{
    int  fac[MAX],exps[MAX];
    int  n, work,count = 0,i, k;

    printf("Input a positive integer:");
    scanf("%d",&n);

    for (i=0,work=n; (work & 0x01UL)==0 && work>1; work>>=1,i++);
    SAVE_FAC(2, i);

    for (k = 3; k <= work; k += 2)
    {
        for (i = 0; work % k == 0 && work > 1; work /= k, i++);
        SAVE_FAC(k, i);
    }

    printf("%d=1", n);
    for (i = 0; i < count; i++)
    {
        while(exps[i]--)
        printf("*%d", fac[i]);
    }
    return 0;
}