IO第一天

fscanf与sprintf拷贝

int main(int argc, const char *argv[])
{
	FILE *fp1=fopen("1.c","r");
	FILE *fp2=fopen("3.c","w");
	char c;
	while(fscanf(fp1,"%c",&c)!=EOF){
		fprintf(fp2,"%c",c);
	}
	return 0;
}

#include<myhead.h>	
int login(const char*);
int regis(const char*);
int main(int argc, const char *argv[])
{
	int chiose=0;
	while(1){
		puts("/t/t1.登入");
		puts("/t/t2.注册");
		puts("/t/t0.退出");
		puts("请输入你的选择");
		scanf("%d",&chiose);
		getchar();
		switch(chiose){
			case 1:{
				   	login(argv[1]);
					break;
				   }
			case 2:{
				   	regis(argv[1]);
					break;
				   }
			case 0:{
				   	exit(EXIT_SUCCESS);
				   }
		}
	}
	return 0;
}

int login(const char *file){
	FILE *fp=fopen(file,"r");
	char name[10], pwd[10];
	char username[10], userpwd[10];
	puts("请输入你的账号");
	fgets(name,sizeof(name),stdin);
	puts("请输入你的密码");
	fgets(pwd,sizeof(pwd),stdin);

	name[strlen(name)-1]='\0';
	pwd[strlen(pwd)-1]='\0';
	if(!fp){
		perror("login");
		return -1;
	}
	while(fscanf(fp,"%s %s",username,userpwd)!=EOF){
		
			printf("%s %s\n",name,pwd);
		if(strcmp(username,name)==0&&strcmp(userpwd,pwd)==0){
			return 0;
		}
	}
	puts("失败");
	fclose(fp);
	
}
int regis(const char *file){
	char username[10];
	char userpwd[10];
	puts("请输入你的账号");
	fgets(username,sizeof(username),stdin);
	puts("请输入你的密码");
	fgets(userpwd,sizeof(userpwd),stdin);
	username[strlen(username)-1]='\0';
	userpwd[strlen(userpwd)-1]='\0';
	FILE *fp=fopen(file,"a");
	if(!fp){
		perror("regis");
		return -1;
	}
	fprintf(fp,"%s %s ",username,userpwd);
	puts("okkkkkkkl");
	fclose(fp);
	
}

文件拷贝

#include<myhead.h>	
int main(int argc, const char *argv[])
{
FILE *fp1=fopen("1.c","r");
if(NULL==fp1){
	perror("fp1");
}
FILE *fp2=fopen("2.c","w");
if(NULL==fp2){
	perror("fp2");
}

char buff[1024];
int res=0;
int count=0;

while(res=fread(buff,1,sizeof(buff),fp1)){
	
	fwrite(buff,1,res,fp2);
	
}

	fclose(fp1);
	fclose(fp2);
	puts("ok");
	fp2=fopen("2.c","r");
	while(1){
		int res=fread(buff,1,sizeof(buff),fp2);		
	

		if(res==0) break;
		printf("%s",buff);
	}
	
	return 0;
}