C语言实现对文件进行操作的示例详解

//打开文件
FILE * fopen ( const char * filename, const char * mode );
//关闭文件
int fclose ( FILE * stream );

#include <stdio.h>
int main()
{
    FILE *pf = fopen("test.txt",'w');
    if(pf==NULL)
    {
        perror("FOPEN:");        //对文件指针进行判断以免返回空指针;
    }
    fput("haohaoxuexi,tiantianxiangshang",pf);
    fclose(pf);
    pf=NULL;            //文件关闭之后把指针置为空，以免出现野指针
}

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <string.h>
#include <malloc.h>

struct student
{
    char name[20];
    int age;
    char adress[20];
}*s1;
int main()
{
    s1 = (struct student*)malloc(sizeof(struct student));
    if (s1 == NULL)
    {
        perror("malloc:");
        return 0;
    }
    FILE* pf = fopen("test.txt", "wb");
    if (pf == NULL)
    {
        perror("FOPEN:");   //对文件指针进行判断以免返回空指针;
        return 0;
    }
    strcpy(s1->name, "陈独秀");
    s1->age = 18;
    strcpy(s1->adress,"东城区箭杆胡同20号");
    fwrite(s1, sizeof(struct student), 1, pf);
    fclose(pf);
    pf = NULL;
}

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <string.h>
#include <malloc.h>

int main()
{
    FILE* pfr = fopen("C:\\Users\\22763\\Pictures\\Saved Pictures\\QQ图片20211001085735.jpg", "rb"); 		//要拷贝的文件目录
    FILE* pfw = fopen("CopyPic.jpg", "wb");
    char temp;
    if (pfw == NULL||pfr==NULL)
    {
        perror("FOPEN:");   //对文件指针进行判断以免返回空指针;
        return 0;
    }
    while (fread(&temp, sizeof(char), 1, pfr))
    {
        fwrite(&temp, sizeof(char), 1, pfw);
    }
    fclose(pfw);
    fclose(pfr);
    pfw = NULL;
    pfr = NULL;
}

int fseek(FILE stream,long offset,int origin );

long ftell( FILE *stream );

void rewind( FILE *stream );