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两个文件copy

​
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int main(int argc, const char *argv[])
{  
	if (argc != 3)   //传参小于3失败
	{
		printf("error");
		printf("./a.out  scrfile destfile");
	
	}
		
	FILE * scr;
	if ((scr = fopen(argv[1],"a+")) == NULL )
	{	
		perror("error\n");
		return -1;
	}
	FILE * dest;
	if ((dest = fopen(argv[2],"a+")) == NULL )
	{
		perror("error\n");
		return -1;
	}
	char arr[20];
	fread(arr,1,sizeof(arr),scr);
	printf("arr=%s\n",arr);
	fwrite(arr,1,strlen(arr),dest);
	fscanf(dest,"%s",arr);
	fclose(scr);
	fclose(dest);

    printf("%s",arr);
	
	

	return 0;
}

​

 

 

1、2023-5-25 14:32:50

2、2023-5-25 14:32:51

3、2023-5-25 14:32:52

//按下ctrl+c,再重新运行程序后

4、2023-5-25 14:33:20

5、2023-5-25 14:33:21

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<time.h>
int main(int argc, const char *argv[])
{  char	new[50] = "";
	char	old[50] = "";

	FILE *fp;
	if ((fp = fopen("./time.txt","a+")) == NULL)
	{
		perror("file error\n");
		return -1;

	}
	int line = 0;
	while (1)
	{	time_t clock = time(NULL);
	struct tm * fomattime = localtime(&clock);
     sprintf(new,"%4d-%2d-%2d %2d:%2d:%2d", fomattime->tm_year+1900\
            ,fomattime->tm_mon+1,\
            fomattime->tm_mday,\
            fomattime->tm_hour,\
            fomattime->tm_min,\
            fomattime->tm_sec);	

		if (strcmp(new,old) != 0)
		{
						fprintf(fp,"%d: %s\n",line++,new);
			fflush(fp);
		}
		strcpy(old,new);
	
	
	
	}

fclose(fp);



	return 0;
}