#include <stdio.h>
#include <string.h>

typedef struct usr{
    char unm[21];
    char pwd[21];
}user;

int main(int argc, const char *argv[])
{
    FILE* userfile=fopen("./user_tible.txt","r");
    printf("输入username:");
    user u;
    scanf("%s",u.unm);
    printf("输入password:");
    scanf("%s",u.pwd);

    char name[21];
    fgets(name,sizeof(name),userfile);
    int len=strlen(name);
    if(name[len-1]=='\n'){
        name[len-1]='\0';
    }
    for(int i=0;i<strlen(name);i++){
        if(name[i]!=u.unm[i]){
            puts("用户名错误");
            return -1;
        }
    }

    char pwd[21];
    fgets(pwd,sizeof(pwd),userfile);
    int len2=strlen(pwd);
    if(pwd[len2-1]=='\n'){
        pwd[len2-1]='\0';
    }
    for(int i=0;i<strlen(pwd);i++){
        if(pwd[i]!=u.pwd[i]){
            puts("密码错误");
            puts(pwd);
            return -1;
        }
    }
    puts("登录成功");
    return 0;
}

作业:拷贝