2023/12/27 work

1. 把课上strcut的练习，尝试着改成class

#include 

using namespace std;

class Stu{
    private:
       int age;
       string sex;
       double height;
    public:
       double score;

       void set_info(int age1,string sex1,double height1);
       int get_age();
       string get_sex();
       double get_height();
       void get_info();

};

void Stu::set_info(int age1, string sex1, double height1){
    age = age1;
    sex = sex1;
    height = height1;
}


int Stu::get_age(){
    return age;
}
string Stu::get_sex(){
    return sex;
}
double Stu::get_height(){
    return height;
}

int main()
{
    Stu s1;
    s1.score = 200;
    s1.set_info(30,"男",172.2);
    //cout << " score= " << s1.score << endl;
    cout << "age = " << s1.get_age() << " sex = " << s1.get_sex() << " heigth = "
         << s1.get_height() << " score= " << s1.score << endl;

    //cout << sizeof(string) << endl;
    return 0;
}

2. 写一个有默认参数的函数，把声明和定义分开，并在主函数内成功调用

#include 

using namespace std;

//定义一个有默认参数的函数

struct Stu{

    public:
    int sum_score(int a,int b=10);
};


int Stu::sum_score(int a,int b){

    return a + b;

}

int main()
{
    Stu stu;
    cout << "sum_score = " << stu.sum_score(80)   << endl;
    return 0;
}

3. 字节对齐

struct data {

char t1 ;     //1

char t2 ;     //1

unsigned short t3 ; //

unsigned long t4 ;  //

};

16 字节

struct data {

char t1 ;    //1 3

int t2 ;       //4

short t3 ;   //2

};   ---> 10 

不是 4 的倍数   12

struct s1

{

char c1 ;   // 1   3

int i ;   //  4

char c2 ;  // 1

};  // 9 

---> 不是 4 的倍数  12

//2 字节对齐

struct s2

{

char c1 ;  //1

char c2 ; //1

int i ; //4

};  

6

typedef struct Test

{

short a ;       //  2  //6

struct

{

int b ;         // 4  +4

double c ; // 8

char d ;    // 1 // 7

};

int e ;  //4

} Test ;

35 不是 4 的  倍数

40 字节

4. 思维导图