#include "stdio.h"
#include "stdlib.h"
#include "string.h"


int main()
{
    FILE *p = fopen("D:\\study\\a.txt", "w");
    fputs("hello world", p);
    fputs("hello world", p);
    fclose(p);
    return 0;
}

判斷檔案是否成功開啟的常用方法

if((fp=fopen("D:\\study\\a.txt","w"))==NULL)
{
  printf("cant open the file"
 
);
  exit(0);
}

copy一個二進位制檔案；(fread(),fwrite())

#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include <time.h>

int main()
{
    char buf[4096];
    FILE *p1 = fopen("D:\\study\\a.zip", "rb");
    FILE *p2 = fopen("D:\\study\\b.zip", "wb");
    while (!feof(p1))
    {
        memset
 
(buf, 0, sizeof(buf));
        size_t res=fread(buf, sizeof(char), sizeof(buf), p1);
        fwrite(buf, sizeof(char), res, p2);
    }
    fclose(p1);
    fclose(p2);
    return 0;
}

獲取檔案基本資訊（stat() ）

#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include <sys/stat.h>

int main()
{
    struct
 
 stat buf;//需要定義結構體 struct stat buf
    stat("D:\\study\\a.zip", &buf);
    printf("file size =%d\n", buf.st_size);//輸出檔案大小
    return 0;
}

統計程式消耗時間（clock()）

#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include "time.h"


int main()
{
    clock_t start_t = clock();
    程式碼塊
    clock_t end_t = clock();
    printf("%d\n",(end_t - start_t));
    return 0;