#include <stdio.h>
#define PASSWORD "1234567"
int verify_password (char *password)
{
    int authenticated;
    authenticated=strcmp(password,PASSWORD);
    return authenticated;
}
main()
{
    int vaild_flag=0;
    char password[1024];
    while(1)
    {
        printf("please input password:");
        scanf("%s",password);
        valid_flag = verify_password(password);
        if(valid_flag)
        {
             printf("incorrect password!\n\n);
        }
         else
        {
             printf("Congratulation! You have passed the verfication!\n");
              break;   
        }
     }
}
这段代码编译时出现错误：
Text1.c(6) : warning C4013: 'strcmp' undefined; assuming extern returning int
Text1.c(17) : error C2065: 'valid_flag' : undeclared identifier
Text1.c(20) : error C2001: newline in constant
D:\VC6.0++\1\Text1.c(21) : error C2143: syntax error : missing ')' before '}'

因为本人刚开始自学C语言底子薄， 希望给帮帮忙！