IO端午作业

 

 

 

 

fopen和fclose 

 错误码

 fgetc和fputc

 fputs

fgets

 

缓冲区

#include 
#include
#include
int main(int argc, const char *argv[])
{
//--------------------------------------验证行缓存-------------------------
	//这种情况不会刷新缓存区
//	printf("hello word");
//	while(1);

	//1.遇到换行符时会刷新缓存区
//	printf("hello word\n");
//	while(1);

	//2.关闭文件指针时会刷新缓存区
//	printf("helllo word");
//	fclose(stdout);
//	while(1);

	//3.程序结束后也会刷新缓存区
//	printf("hello word");

	//4.输入输出切换时也会刷新缓存区
//	int num;
//	scanf("%d",&num);
//	printf("%d\n",num);
//	while(1);

	//5.使用fflush函数刷新缓存区
//	printf("hello word");
//	fflush(stdout);
//	while(1);

	//6.缓存区已满
//	for ( int i = 0; i < 1025; i++ )
//	{
//		printf("A");
//	}
//	while(1);

//---------------------------------------验证全缓存--------------------------
	FILE*fp;//定义一个文件指针
	//以只写的形式打开一个文件
	if ((fp = fopen("04test.txt","w")) == NULL)
	{
		perror("fopen error");
		return -1;
	}

	//1.关闭文件指针时会刷新缓存区
//	fputs("helllo word\n",fp);
//	fclose(fp);
//	while(1);

	//2.程序结束后也会刷新缓存区
//	fputs("helllo word\n",fp);
	//3.使用fflush函数刷新缓存区
	
//	fputs("helllo word\n",fp);
//	fflush(fp);
//	while(1);
//	4.输入输出切换时也会刷新缓存区
	
//	char s[128];
//	fputs("hello word\n",fp);
//	fgets(s,sizeof(s),fp);
//	printf("%s\n",s);
//	while(1);

	//5.当全缓存满时也会刷新缓存区
	for(int i = 0; i < 5000; i++)
	{
		fputc('A',fp);
	}
	while(1);
	return 0;
}

 时间函数和sprintf

 snprintf

 fscanf和fprintf

 fread和fwrite

1.读写字符串

 读写整形变量

 读取结构体信息

 feof

 关于光标的函数

 

 

 

#include 
#include 

typedef struct{
    unsigned int img_size; //图片的大小
    unsigned int img_width;//图片的宽
    unsigned int img_high; //图片的高
    unsigned short img_bitcount; //一个像素点占用的bit(24bit)
}image_info_t;

typedef struct{
    unsigned char b;
    unsigned char g;
    unsigned char r;
}point_t;

void show_image_info(image_info_t *info)
{

    printf("size = %d,width = %d,high = %d,bitcount = %d\n",
    info->img_size,info->img_width,info->img_high,info->img_bitcount);
}

void get_image_info(FILE*fp,image_info_t *info)
{
    fseek(fp,2,SEEK_SET);
    fread(&info->img_size,1,4,fp); //图片的大小

    fseek(fp,18,SEEK_SET);
    fread(&info->img_width,1,4,fp); //图片的宽

    fread(&info->img_high,1,4,fp); //读取图片的高

    fseek(fp,2,SEEK_CUR);
    fread(&info->img_bitcount,1,2,fp); //像素点占用的bit
}

void copy_image_file(FILE*sfp,FILE*dfp)
{
    int ret;
    char buf[1024] = {0};
    
    while(!(feof(sfp)||ferror(sfp))){
        ret = fread(buf,1,sizeof(buf),sfp);
        fwrite(buf,1,ret,dfp);
    }
    
    return;
}
void set_image_mosaic(FILE *fp,image_info_t *info,int x,int y)
{
    int i,j,k,w;
    point_t color = {0,0,0xff};
    char *buffer = (char *)malloc((info->img_width)*(info->img_high)*3);
    //point_t arr[612][440];
    //1.将图像读取回来
    fseek(fp,54,SEEK_SET);
    fread(buffer,1,(info->img_size-54),fp);
    //2.修改
    //i:整体的高/10
    //j:整体的宽除以10
    //k:块的高
    //w:块的宽
    for(i=0;iimg_high/y;i++){
        for(j=0;jimg_width/x;j++){
            //读取小方块中最左上角的像素点
            color = *(point_t *)(buffer+(j*3*x)+(i*y*info->img_width*3));
            for(k=0;kimg_width*3)+
                      (j*3*x)+(i*y*info->img_width*3)) = color;
                }
            }
        }
    }

    //3.重新将图像写回去
    fseek(fp,54,SEEK_SET);
    fwrite(buffer,1,(info->img_size-54),fp);
}
int main(int argc, char const *argv[])
{
    FILE *sfp,*dfp;
    int size;
    image_info_t info;
    char new_name[20] = {0};

    if(argc != 2){
        fprintf(stderr,"input error,try again\n");
        fprintf(stderr,"usage:./a.out xxxx.bmp\n");
        return -1;
    }
    //1.打开文件并拷贝文件 milaoshu.bmp
    if((sfp = fopen(argv[1],"r"))==NULL)
        PRINT_ERR("open error");
    
    //构造一个新图片的字符串  new_milaoshu.bmp
    snprintf(new_name,sizeof(new_name),"new_%s",argv[1]);

    //打开新图片，如果不存在就创建，如果存在就清空
    if((dfp = fopen(new_name,"w+"))==NULL)
        PRINT_ERR("open error");

    //图片的拷贝，将milaoshu.bmp-->new_milaoshu.bmp    
    copy_image_file(sfp,dfp);

    //2.获取图片前54个字节中有用的信息
    get_image_info(dfp,&info);

    show_image_info(&info);

    //3.尝试打马赛克
    //10,10:代表的是打马赛克每个小方块的大小
    //10*3= 30
    //10  = 10行
    set_image_mosaic(dfp,&info,10,10);

    //4.关闭源文件和目标文件
    fclose(sfp);   
    fclose(dfp); 
    return 0;
}