#include <stdio.h>
#include <string.h>
#include <stdlib.h>
struct sysuser {
    char username[20];
    char password[8];
};
int main(void) {
    FILE *fp1,*fp2;
    int i;
    void encrypt(char *pwd);
    struct sysuser su;

    if((fp1 = fopen("f12-2.txt", "r")) == NULL) { /*以只读形式打开f12-2.txt文件*/
        printf("f12-2.txt open error!\n"); 
				exit(0);
    }
    if((fp2 = fopen("f12-3.txt", "w")) == NULL) {  /*以只写形式打开或创建f12-3.txt文件*/
      	printf("f12-3.txt open error!\n"); 
				exit(0);
    }
    for(i = 1; i <= 5; i++) {

      	fscanf(fp1,"%s%s", su.username, su.password);/*从f12-2.txt文件中读取信息*/

      	fprintf(fp2,"%s %s\n", su.username, su.password);/*将f12-2.txt文件中信息写入f12-3.txt文件*/ 
    }
    if(fclose(fp1)) {                               /*关闭f12-2.txt文件*/ 
        printf("Can not close the f12-2.txt!\n"); 
        exit(0);
    }
    if(fclose(fp2)) {                              /*关闭f12-3.txt文件*/
        printf("Can not close the f12-3.txt!\n"); 
        exit(0);
    }
    return 0;
}