程序代码：

#include<stdio.h>

int main()
{
    FILE *fp;
    char size[1000001]="";
    int num,i,count=0;

    if((fp=fopen("F:\\aa.txt","r"))==NULL)
    {
        printf("open the file error!\n");
        return 0;
    }
    for(i=0;i<1000000;i++)
    {
        if(feof(fp))
            break;
        fscanf(fp,"%d",&num);
        if(size[num]==0)
        {
            size[num]='1';
            count++;
        }
    }
    printf("count=%d\n",count);

    fclose(fp);
    return 0;
}

程序代码：

//先在文件F:\\aa.txt中存放N个正整数M1,M2,....MN,(0< Mk <10000000)，程序如下
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char* argv[])
{
    FILE *fp;

    char *size=(char *)malloc(10000000/8);
    memset(size,0,10000000/8);
    int num,i,count=0;

    if((fp=fopen("F:\\aa.txt","r"))==NULL)
    {
        printf("open the file error!\n");
        return 0;
    }
    for(i=0;i<10000000;i++)
    {
        if(feof(fp))
            break;
        fscanf(fp,"%d",&num);
        if((size[num/8]&(1<<num%8)) == 0)
        {
            size[num/8] |=(1<<num%8);
            count++;
        }
    }
    printf("count=%d\n",count);

    free(size);
    fclose(fp);
    return 0;
}