c++标准输入输出

• 用cout + << 来实现输出
• C++支持C语言的格式控制字符
• 用endl替换"n"换行

#include 
using namespace std;			 //用来缺省std前缀的
struct MM
{
	char name[20];
	int age;
	int num;
};
int main()
{
	//单个数据输出
	std::cout << "ILoveyou";		//如果没有写using namespace std; 必须加前缀
	cout << 1;

	//多个数据的输出
	cout << "n";
	cout << "姓名t" << "年龄t" << "编号n";
	struct MM mm = { "mm",18,1001 };
	//输出方式1
	cout << mm.name << "t" << mm.age << "t" << mm.num << "n";
	//输出方式2
	cout << mm.name << "t";
	cout << mm.age << "t";
	cout << mm.num << "n";
	cout << endl;				//等效:cout<<"n";
	std::cout << std::endl;		//一样的是std命名空间中的
	return 0;
}

• 用cin+ >> 来实现输入
• 输入不需要任何的格式控制字符

#include 
using namespace std;			 //缺省std前缀的
struct MM 
{
	char name[20];
	int age;
	int num;
};
int main() 
{
	//单个数据输入
	cout << "请输入一个整数:";
	int num;
	cin >> num;			//变量名
	cout << num << endl;
	cout << "请输入一个字符串:";
	char str[20];
	while (getchar() != 'n');		//存在跳过显现:清空缓冲区
	cin >> str;							//数组名
	cout << str << endl;
	//接受空格的输入--->了解
	cin.getline(str, 10);		//gets_s(str, 10);
	cout.write(str, 10);
	
	//多个数据输入
	cout << "input num and str:";
	cin >> num >> str;
	cout << num << "t" << str << endl;
	
	cout << "input name,age,num:";
	struct MM temp;
	cin >> temp.name >> temp.age >> temp.num;
	cout << "姓名t年龄t编号" << endl;
	cout << temp.name << "t" << temp.age << "t" << temp.num << endl;
	return 0;
}

#include
#include
#include
using namespace std;

void Input(char* userName, char* passWord)
{
    //输入用户名
    cin >> userName;
    //登录实现密码不可见
    char pass;
    while ((pass = _getch()) != 'r')
    {
        cout << "*";
        *passWord = pass;
        passWord++;
    }
}
int  Login(char* username, char* passWord, const char* root = "root", const char* pass = "12345")
{
    //比较验证 
    if (strcmp(username, root) == 0)
    {
        if (strcmp(passWord, pass) == 0)
        {
            return 1;
        }
    }
    return 0;
}
int main()
{
    char userName[20];
    char passWord[7]={0};
    Input(userName, passWord);
    if (Login(userName, passWord) == 1)
    {
        cout << "n登录成功";
    }
    else
    {
        //打印用户名和密码错误   
        cout << "n用户名或密码错误！！！";
    }
    return 0;
}