File operations (sorting)

Text files, each row represents an integer in the range 0 to 512;

Requirements: Sort files, do not use heap space, only stack space.

 

Function generator with a certain amount of srand () and rand () Random Number

/***
file.c
***/
#include<stdio.h>
#include<string.h>
#include<time.h>
const int maxn = 100000;
int main()
{
    srand((unsigned int)time(NULL));
    int i;
    FILE *p = fopen("./a.txt","w");
    for(i = 0; i < maxn; i++)
    {
        fprintf(p,"%d\n",(int)rand() % 513);
    }
    fclose(p);
    return 0;
}

Then sort by:

/***
sort.c
***/
#include<stdio.h>
#include<string.h>
#include<time.h>

int main()
{
    int i;
    FILE *p = fopen("./a.txt","r");
    int array[513] = {0};
    while(!feof(p))
    {
        char buf[100] = {0};
        fgets(buf,sizeof(buf),p);
        if(0 != buf[0])
        {
            int value = atoi(buf);
            array[value]++;
        }
    }
    fclose(p);
    
    p = fopen("./b.txt","w");
    int j;
    for(i = 0; i < 513; i++)
    {
        for(j = 0; j < array[i]; j++)
        {
            fprintf(p,"%d\n",i);
        }
    }
    fclose(p);
    return 0;    
}