Structure array, pointer and function and application cases

1、 Array of structs

  effect ： The function of structure array is to put the customized structure into the array for convenient maintenance

​
// Structure definition 
struct sanguo// three countries 
{
	string name;// full name 
	int age;    // Age 
	string sex; // Gender 
};
int main()
{
	// Array of structs 
	struct sanguo hero[5] = {
		{" Liu bei ",23," male "},
		{" Guan yu ",22," male "},
		{" Zhang Fei ",20," male "},
		{" zhaoyun ",21," male "},
		{" The sable cicada ",19," Woman "},
	};// initialization 
system("pause");
return 0;
}

​

2、 Structure pointer

effect ： Access members in the structure through pointers

                  Using operators -> You can access structure properties through structure pointers

​
#include<string>
#include<iostream>
using namespace std;
// Structure definition  
struct student
{
	string name;// full name  
	int age;    // Age  
	int score;  // fraction  
};
int main()
{ 
// Create student structure variables  
	struct student stu={" Ningzi ",20,100};
// Pointer to a struct variable  
	struct student *p=&stu;
// Access variables in the structure through pointers 
    p->score=59;
// Output structure 
    cout<<" The student's name ："<<stu.name <<"\n"<<" Student age ："<<stu.age <<"\n"<<" Students' scores ："<<stu.score<<endl;
	system("pause");
	return 0;
 } 

​

We accessed the student's grades through the structure pointer and made modifications

  It can be seen that through pointer access, we can change the student's grades from 100 Change it to 59（ Sorry, ningzi ）

Of course, we can also access other variables through the structure pointer

 cout<<" The student's name ："<<p->name <<"\n"<<" Student age ："<<p->age <<"\n"<<" Students' scores ："<<p->score<<endl;

  summary   Structure pointers can be accessed through '->' Access structure members

Structure pointer accesses structure array

#include<string>
#include<iostream>
using namespace std;
// Define student structure  
struct student
{
	string name;// full name  
	int age;    // Age  
	int score;  // fraction  
};
int main()
{ 
    int i;
    struct student stu[3];// Create structure  
	struct student *p=stu;// The array itself represents the address   So don't add &
    for(i=0;i<3;i++,*p++)
	{
		cin>>p->name>>p->age>>p->score;// Circular input structure array  
	 } 
    for(i=0;i<3;i++)
	{
		// Cyclic output  
		cout<<stu[i].name<<"\n"<<stu[i].age<<"\n"<<stu[i].score<<endl;
	 } 
	system("pause");
	return 0;
 } 

3、 Structure nested structure

A member of a structure can be another structure

For example, a teacher takes a student , A teacher's structure records a student's structure

// Define student structure  
struct student
{
	string name;// full name  
	int score;  // fraction  
};
// Define the teacher structure  
struct teacher 
{ 
    string name;
    struct student stu;// The teacher takes a student  
};

How to access, how to access

struct teacher th;// Create structure  
    th.name=" Li lei ";
	th.stu.name=" Zhang San ";
	th.stu.score=88; 

We can also use structure pointers to access

struct teacher *p=&th; 
    p->name=" Li lei ";
	p->stu.name=" Zhang San ";
	p->stu.score=88; 

4、 Structure is used as function parameter （ Value passed ）

effect : Pass the structure as a parameter to the function

#include<string>
#include<iostream>
using namespace std;
// Define student structure  
struct student
{
	string name;// full name  
	int age;    // Age  
	int score;  // fraction  
};
void outstruct(struct student q);// Structure output function 
int main()
{ 
    int i; 
    struct student stu={" Zhang San ",18,100};// Create structure  // initialization  
    outstruct(stu); 
	return 0;
}
void outstruct(struct student q)
{
	cout<<q.name<<endl;
	cout<<q.age<<endl;
	cout<<q.score<<endl;
}

 

  It should be noted that this transfer only passes the value of the structure Modifying parameters in a function does not affect the values in the main function

void outstruct(struct student q)
{
	q.age=55;// Make... In a function age=55
	cout<<q.name<<endl;
	cout<<q.score<<endl;
    cout<<"in outstruct: age= "<<q.age<<endl;
}
// stay main Function to do the following 
    outstruct(stu); 
    cout<<"in main: age= "<<stu.age;

  It can be seen that main Medium age No change has been made

5、 Structure pointer as function parameter （ Address delivery ）

#include<string>
#include<iostream>
using namespace std;
// Define student structure  
struct student
{
	string name;// full name  
	int age;    // Age  
	int score;  // fraction  
};
void getstruct(struct student *q);// Input structure function 
int main()
{ 
    struct student stu;// Create structure  
    getstruct(&stu); 
    cout<<stu.name<<"\n"<<stu.age<<"\n"<<stu.score<<endl;// Output 
	return 0;
}
void getstruct(struct student *q)
{
	cin>>q->name;
	cin>>q->score;// Input 
	cin>>q->age;
}

   It should be noted that this kind of transmission passes the address of the structure   Changing parameters in a function will affect the values in the main function

6、 Structure case 1

Case description ： A teacher in the school takes five students , There are three teachers in all , Design the structure of students and teachers The teacher structure includes the teacher's name and the structure of five students , The student structure includes names and test scores , Create an array to save three teachers , Assign values to teachers and students through functions , Output teacher data and student data through functions .

The complete code is as follows

#include<string>
#include<iostream>
using namespace std;
// Define student structure  
struct student
{
	string name;
	int score;
};
// Define the teacher structure  
struct teacher
{
	string name;
	struct student xs[5];// Contains an array of student structures （5） 
}ls[3];// Create an array of teacher structures  
void getstruct(struct teacher *tc);// Structure input function  
void outstruct(struct teacher *q);// Structure output function  
int main()
{
	getstruct(ls);
	outstruct(ls);
	return 0;
}
void getstruct(struct teacher* tc)
{
	int i,j;
	for (i = 0; i < 3; i++, *tc++)
	{
		cin >> tc->name;
		for (j = 0; j < 5; j++)
		{
			cin >> tc->xs[j].name;// loop  
			cin >> tc->xs[j].score;// Input  
		}
	}
}
void outstruct(struct teacher *q)
{
	int i, j;
	cout<<endl; 
	for (i = 0; i < 3; i++)
	{
       cout << q->name<<endl;
	   for (j = 0; j < 5; j++)
	   {
		   cout << q->xs[j].name<<" ";// loop  
		   cout << q->xs[j].score<<endl;// Output  
	   }
	}
}

  Structure case 2

Case description ：

Design the structure of a hero, including the name Age Gender , Create an array of structs , Five heroes are stored in the array , Through bubble sorting, the heroes in the array are sorted in ascending order according to their ages , Print the structure array after sorting .

Here are the five heroes

        {" Liu bei ",23," male "},
        {" Guan yu ",22," male "},
        {" Zhang Fei ",20," male "},
        {" zhaoyun ",21," male "},
        {" The sable cicada ",19," Woman "},

The complete code is as follows ：

#include<string>
#include<iostream>
using namespace std;
// Define the hero structure  
struct sanguo
{
	string name;
	int age;
	string sex;
};
int main()
{
	int i,j;
	// Create an array of hero structures  
	struct sanguo hero[5] = {
		{" Liu bei ",23," male "},
		{" Guan yu ",22," male "},
		{" Zhang Fei ",20," male "},
		{" zhaoyun ",21," male "},
		{" The sable cicada ",19," Woman "},
	};
	struct sanguo alg;// Create intermediate structure variables  
	for (i = 0; i < 5; i++)
	{
	for(j=0;j<4;j++)
	{
		if (hero[j].age > hero[j + 1].age)
		{
			alg = hero[j];
			hero[j] = hero[j + 1];// Bubble sort  
			hero[j + 1] = alg;
		}
	}
}
	for(i=0;i<5;i++)
	{
		// Output structure array  
		cout << hero[i].name << hero[i].age << hero[i].sex << endl;
	}
	return 0;
}