8. 結構體

結構體屬於使用者自定義的資料型別，允許使用者儲存不同的資料型別

8.1 結構體的定義和使用

注：
1、定義結構體時的關鍵字是struct，不可以省略；
2、建立結構體變數時，關鍵字 struct 可以省略；
3、結構體變數利用操作符 “.” 訪問成員。

#include<iostream>
#include<string>
using namespace std;

struct student
{
	string name;
	int age;
	int score;
}s3;

int main()
{
	//通過學生型別建立具體學生
	struct student s1;
	s1.age = 16;
	s1.name = "張三";
	s1.score = 60;

	cout << "姓名：" << s1.name << " 年齡：" << s1.age << " 分數：" << s1.score << endl;

	struct student s2 = { "李四",78,50 };
	cout << "姓名：" << s2.name << " 年齡：" << s2.age << " 分數：" << s2.score << endl;

	s3.name = "王五";
	s3.age = 20;
	s3.score = 60;
	cout << "姓名：" << s3.name << " 年齡：" << s3.age << " 分數：" << s3.score << endl;

	system("pause");
	return 0;
}

8.2 結構體陣列

#include<iostream>
#include<string>
using namespace std;

//1、定義結構體
struct student 
{
	string name;
	int age;
	int score;
};

int main()
{
	//2、建立結構體陣列
	struct student stuArray[3]
	{
		{"張三",18,80},
		{"李四", 28, 90},
		{"王五", 38, 99}
	};
	//3、給結構體陣列中的元素賦值
	stuArray[2].name = "趙六";
	stuArray[2].age = 19;
	stuArray[2].score = 85;

	//4、遍歷結構體陣列
	for (int i = 0; i < 3; i++)
	{
		cout << "姓名：" <<stuArray[i].name 
			 << "年齡：" <<stuArray[i].age 
			 << "分數：" <<stuArray[i].score 
			 << endl;
	}
	system("pause");
	return 0;
}

8.3 結構體指標

作用：利用指標訪問結構體中的成員。

• 利用操作符 -> 可以通過結構體指標訪問結構體屬性。

# include<iostream>
# include<string>

using namespace std;

//建立結構體變數
struct student 
{
	string name;
	int age;
	int score;

};


int main()
{
	//建立學生結構體變數
	struct student s = { "張三",48,80 };
	//通過指標指向結構體變數
	struct student *p = &s;
	//通過指標訪問結構體變數中的資料
	cout << "姓名：" << p->name << "年齡：" << p->age << "成績：" << p->score << endl;

	system("pause");
	return 0;

}

8.4 結構體巢狀結構體

作用：結構體中的成員可以是另一個結構體。
例如：每個老師輔導一個學員，一個老師的結構體中，記錄一個學生的結構體。

# include<iostream>
# include<string>

using namespace std;

//定義結構體
struct student
{
	string name;
	int age;
	int score;
};


struct teacher
{
	int id;
	string name;
	int age;
	struct student stu;
};



int main()
{
	//建立老師結構體變數
	teacher t;
	t.id = 10000;
	t.name = "老王";
	t.age = 50;
	t.stu.age = 18;
	t.stu.name="小李";
	t.stu.score = 90;

	cout << "老師姓名： " << t.name << "老師id： " << t.id
		<< "老師年齡：" << t.age << "學生年齡：" << t.stu.age
		<< "學生姓名：" << t.stu.name
		<< "學生成績：" << t.stu.score << endl;

	system("pause");
	return 0;

}

8.5 結構體作函式引數

# include<iostream>
# include<string>

using namespace std;

//定義結構體
struct student
{
	string name;
	int age;
	int score;
};
//1、值傳遞
void printstudent(struct student s)
{
	cout << "姓名：" << s.name << "年齡：" << s.age << "分數：" << s.score << endl;
}

//2、地址傳遞
void printstudent2(struct student *p)
{
	cout << "姓名：" << p->name << "年齡：" << p->age << "分數：" << p->score << endl;
}

int main()
{
	//建立老師結構體變數
	struct student s;
	s.name = "張三";
	s.age = 20;
	s.score = 60;

	printstudent(s);
	printstudent2(&s);

	system("pause");
	return 0;

}

8.6 結構體中const使用場景

# include<iostream>
# include<string>

using namespace std;

//定義結構體
struct student
{
	string name;
	int age;
	int score;
};
//將函式中的形參改為指標，可以節省記憶體空間，而且不會賦值新的副本出來
void printstudent( const struct student *s)
{
	cout << "姓名：" << s->name << "年齡：" << s->age << "分數：" << s->score << endl;
}

int main()
{
	//建立結構體變數
	struct student s;
	s.name = "張三";
	s.age = 20;
	s.score = 60;

	printstudent(&s);
	
	system("pause");
	return 0;
}

8.7 結構體案例1

# include<iostream>
# include<string>
# include<ctime>

using namespace std;

//定義結構體
struct student
{
	string name;
	int score;
};

struct teacher
{
	string name;
	struct student sArray[5];

};

void allocateSpace(struct teacher tArray[] ,int len)
{
	string nameseed = "ABCDE";
	for (int i = 0; i < len; i++)
	{
		tArray[i].name = "Teacher_";
		tArray[i].name += nameseed[i];
		for (int j = 0; j < 5; j++)
		{
			tArray[i].sArray[j].name = "Student_";
			tArray[i].sArray[j].name += nameseed[j];

			int random = rand() % 61 + 40;//產生40~100之間的隨機數
			tArray[i].sArray[j].score = random;
		}
	}
}

void printInfo(struct teacher tArray[], int len)
{
	for (int i = 0; i < len; i++)
	{
		cout << "老師姓名：" << tArray[i].name << endl;
		for (int j = 0; j < 5; j++)
		{
			cout << "\t學生姓名: " << tArray[i].sArray[j].name;
			cout << "	考試分數：" << tArray[i].sArray[j].score << endl;
		}
	}
}


int main()
{
	//隨機數種子
	srand((unsigned int)time(NULL));

	//1、建立3名老師的陣列
	struct teacher tArray[3];
	//2、通過函式給3名老師的資訊賦值，並給老師帶的學生資訊賦值
	int len = sizeof(tArray) / sizeof(tArray[0]);
	allocateSpace(tArray, len);
	//3、列印所有老師及所帶學生的資訊
	printInfo(tArray,len);

	system("pause");
	return 0;
}

8.8 結構體案例2

# include<iostream>
# include<string>

using namespace std;

//1、定義英雄結構體
struct hero
{
	string name;
	int age;
	string sex;
};

void bubbleSort(struct hero array[], int len)
{
	for (int i = 0; i < len - 1; i++)
	{
		for (int j = 0; j < len - i - 1; j++)
		{
			if (array[j].age > array[j + 1].age)
			{
				string temp = array[j + 1].name;
				array[j + 1].name = array[j].name;
				array[j].name = temp;
			}
		}
	}
}


void printhero(struct hero array[], int len)
{
	for (int i = 0; i < len; i++)
	{
		cout << "英雄姓名：" << array[i].name
			<< "  英雄年齡：" << array[i].age
			<< "  英雄性別：" << array[i].sex << endl;
	}
}

int main()
{
	//2、建立英雄結構體陣列存放5名英雄
	struct hero array[5]
	{
		{"劉備",23,"男"},
		{"關羽",22,"男"},
		{"張飛",20,"男"},
		{"趙雲",21,"男"},
		{"貂蟬",19,"女"},
	};

	int len = sizeof(array) / sizeof(array[0]);
	/*for (int i = 0; i < len; i++)
	{
		cout << "英雄姓名：" << array[i].name
			<< "  英雄年齡：" << array[i].age
			<< "  英雄性別：" << array[i].sex << endl;
	}*/
	//3、對陣列進行排序，按照年齡進行升序排序
	bubbleSort(array, len);

	//4、將排序結果列印輸出
	printhero(array, len);

	system("pause");
	return 0;
}