#include <iostream>
#include <windows.h>
 
using namespace std;
 
class Student {
public:
    string name;
    int num;
 
    Student(const string &name, int num) : name(name), num(num) {}
 
    friend ostream &operator<<(ostream &os, const Student &student) {
        os << "name: " << student.name << " num: " << student.num;
        return os;
    }
};
 
int main() {
    SetConsoleOutputCP(CP_UTF8);
    Student s("張三", 1001);
    cout << s << endl;
    return 0;
}

#include <cstring>
#include <iostream>

using namespace std;

int main()
{
    /* 
    <<運算符  (可以進行 混合 拼接輸出)
    */
    const char *s = "hhhhh";                                //字符串是const char*類型的，所以將字符串賦值給 char* 類型要加const關(guān)鍵字
    cout << "the length of the s is " << strlen(s) << endl; // strlen()是cstring庫中的函數(shù)
    char str[10] = "ddddd";
    cout << "hello" << endl;
    cout << s << str << endl; //可以進行拼接輸出
    // 如何打印字符串地址的值？
    //對于其他類型的指針，c++將其對應(yīng)于void*，并打印地址的數(shù)值表示。如果要獲得字符串的地址，則必須將其強制類型轉(zhuǎn)換成其他類型
    cout << &str[0] << endl;        //invalid
    cout << (float *)s << endl;     //valid
    cout << (void *)str << endl;    //valid
    cout << (int *)"hello" << endl; //valid
    cout << "-------------------------------------------\n";
    /*
    put()方法  (可以進行 混合 拼接輸出)
    用于顯示字符 (也可以將int型的賦給它，它會將int轉(zhuǎn)換成char，從而顯示與該ascll碼相對應(yīng)的字符)
    */
    cout.put('d');
    cout.put('\n');
    cout.put('d').put('b').put('\n'); //可以進行拼接輸出
    cout.put(65);
    cout.put(65.9); //put 浮點數(shù)65.9強制類型轉(zhuǎn)換成整型數(shù)65（向下取整）
    cout.put('\n');
    cout << "-------------------------------------------\n";

    /*
    write()方法  (可以進行 混合 拼接輸出)
    第一個參數(shù)提供了要顯示的字符串的地址，第二個參數(shù)指出要顯示多少個字符
    */
    const char *state1 = "Florida";
    const char *state2 = "Kansas";
    //state1、state3用于提供state2前面和后面的數(shù)據(jù)，以便程序員知道程序錯誤存取state2時發(fā)生的情況
    const char *state3 = "Euphoria";

    int len = strlen(state2);
    cout << "Increasing loop index:\n";
    int i;
    for (i = 1; i <= len; i++)
    {
        cout.write(state2, i);
        cout << endl;
    }
    // concatenate output
    cout << "Decreasing loop index:\n";
    for (i = len; i > 0; i--)
        cout.write(state2, i) << endl;
    // exceed string length
    cout << "Exceeding string length:\n";
    //我們發(fā)現(xiàn)：連續(xù)定義的字符串時連續(xù)存儲的，中間用一個空格隔開 ?。∵@可能因為編譯器之間的差別而有所不同
    cout.write(state2, len + 5).write("\n", 1).write(state2, len + 4) << endl;

    /*
    write()也可以用于數(shù)值數(shù)據(jù)，您可以將數(shù)字的地址強制轉(zhuǎn)換成char*，然后傳遞給他
    但這不會將數(shù)字轉(zhuǎn)換為相應(yīng)的字符，而是傳輸內(nèi)存中儲存的位表示。例如4字節(jié)的long值將作為四個獨立的字節(jié)被傳輸，
    輸出設(shè)備將把每個字節(jié)作為ASCLL碼進行解釋，最終顯示出來的是四個字符的組合（有可能是亂碼）
    */
    long val = 1094795585; // 二進制數(shù)01000001010000010100000101000001所對應(yīng)的十進制數(shù)(每個字節(jié)都是65)
    cout.write((char *)&val, sizeof(long)).write("\n", 1);
    cout << "-------------------------------------------\n";

    /*
    刷新輸出緩存區(qū)
    */
    cout << "Hello, good-looking! " << flush;
    cout << "Wait just a moment, please." << endl; //endl 刷新緩沖區(qū)，并插入一個換行符
    flush(cout);
    cout << flush; //ostream類對<<插入運算符進行了重載，使得下述表達式將被替換位函數(shù)調(diào)用flush(cout);
    return 0;
}

#include <iostream>

using namespace std;

int main()
{

    int n = 10;
    cout << "n\n";
    cout << n << " (decimal)\n";
    cout << hex << n << " (hexadecimal)\n";
    cout << oct << n << " (octal)\n";
    dec(cout); // ostream類重載了<<運算符，這使得上述用法與函數(shù)調(diào)用dec（cout）等價
    cout << n << " (decimal)\n";
    cout << "-------------------------------------------\n";

    //width()  只影響接下來顯示的一個項目，然后字段寬度將恢復為默認值 0
    int w = cout.width(2); //width(int i)返回的是修改前字段寬度的值，而不是剛設(shè)置的值
    //fill(char c) 它更改的填充字符將一直有效，直到再次更改它為止
    cout.fill('*');
    cout << "default field width = " << w << ":\n"; //C++的原則：顯示所有的數(shù)據(jù)比保持列的整潔更重要。輸入上面設(shè)置了字段寬度為2，但這里依舊能將字符串“default field width = ”顯示全
    cout.width(5);
    cout << "N"
         << ":\n";

    for (long i = 1; i <= 100; i *= 10)
    {
        cout.width(5);
        cout << i << ":\n";
    }
    cout << "-------------------------------------------\n";

    //設(shè)置浮點數(shù)的精度
    float price1 = 20.40;
    float price2 = 1.9 + 8.0 / 9.0;

    cout << "\"Furry Friends\" is $" << price1 << "!\n";
    cout << "\"Fiery Fiends\" is $" << price2 << "!\n";

    cout.precision(2); //修改輸出浮點數(shù)的精度為2，設(shè)置后一直有效，直到再次更改它為止
    cout << "\"Furry Friends\" is $" << price1 << "!\n";
    cout << "\"Fiery Fiends\" is $" << price2 << "!\n";

    cout.precision(6);
    cout.setf(ios_base::showpoint); //showpoint是ios_base類聲明中定義的類級靜態(tài)常量，在成員函數(shù)的定義外面使用要加上作用域運算符（：：）
    cout << "\"Furry Friends\" is $" << price1 << "!\n";
    cout << "\"Fiery Fiends\" is $" << price2 << "!\n";

    cout.precision(2);
    cout << "\"Furry Friends\" is $" << price1 << "!\n";
    cout << "\"Fiery Fiends\" is $" << price2 << "!\n";

    cout << "-------------------------------------------\n";

    int temperature = 63;
    cout << "Today's water temperature: ";
    cout.setf(ios_base::showpos); // show plus sign
    cout << temperature << endl;

    cout << "For our programming friends, that's\n";
    cout << std::hex << temperature << endl; // use hex
    cout.setf(ios_base::uppercase);          // use uppercase in hex
    cout.setf(ios_base::showbase);           // use 0X prefix for hex
    cout << "or\n";
    cout << temperature << endl;
    cout << "How " << true << "! oops -- How ";
    cout.setf(ios_base::boolalpha);
    cout << true << "!\n";

    cin.get();
    return 0;
}