一、结构体定义
结构体属于用户自定义的类型,允许用户存储不同的数据类型。
语法:struct 结构体名{结构体成员列表};
通过结构体创建变量有三种方式:
一般使用前两种,因为第三种在定义时创建的变量容易被人所忽略。
#include <iostream>
using namespace std;
struct Student {
string name;
int age;
float score;
}s3;
int main() {
//创建的时候struct关键字可以省略
struct Student s1;
s1.name = "tom";
s1.age = 12;
s1.score = 99;
cout << "name:" << s1.name << "age:" << s1.age << "score:" << s1.score << endl;
struct Student s2 ={"jack", 15, 98};
s3.name = "bob";
s3.age = 19;
s3.score = 97;
system("pause");
return 0;
}
二、结构体数组
作用:将自定义的结构体放入到数组中方便维护。
语法:struct 结构体名 数组名[元素个数] = {{},{},...{}}
#include <iostream>
using namespace std;
struct Student {
string name;
int age;
float score;
};
int main() {
//结构体数组定义
struct Student stuArr[3]
{
{ "tom", 19, 99},
{ "jack",15, 98},
{ "bob", 22, 97 },
};
//可以修改值或者在这里进行赋值
stuArr[2].name = "mike";
//获取数组的长度
int length = sizeof(stuArr) / sizeof(stuArr[0]);
//遍历数组
for (int i = 0; i < length; i++) {
cout << stuArr[i].name << stuArr[i].age << stuArr[i].score << endl;
}
system("pause");
return 0;
}
三、结构体指针
作用:通过指针来访问结构体中的成员
#include <iostream>
using namespace std;
struct Student {
string name;
int age;
float score;
};
int main() {
struct Student s = { "tom",12,99 };
Student* p = &s;
//需要使用->来访问
cout << p->name << p->age << p->score << endl;
system("pause");
return 0;
}
四、结构体嵌套结构体
#include <iostream>
using namespace std;
struct Student {
string name;
int age;
float score;
};
struct Teacher {
int id;
string name;
int age;
Student stu;
};
int main() {
struct Teacher t;
t.id = 1;
t.name = "joke";
t.age = 45;
struct Student stu = { "tom",12,99 };
t.stu = stu;
cout << t.id << t.name << t.age << t.stu.name << t.stu.age << t.stu.score << endl;
system("pause");
return 0;
}
五。结构体做函数参数
作用:将结构体作为参数向函数传递。
传递方式有两种:值传递、引用传递。
值传递:
#include <iostream>
using namespace std;
struct Student {
string name;
int age;
float score;
};
//值传递
void printStudent(Student stu) {
stu.name = "jack";
stu.age = 22;
stu.score = 90;
cout << "结构体中的stu信息:" << endl;
cout << stu.name << "," << stu.age << "," << stu.score << endl;
}
int main() {
struct Student stu = { "tom",12,99 };
cout << "未传入函数之前的结构体值:" << endl;
cout << stu.name << "," << stu.age << "," << stu.score << endl;
printStudent(stu);
cout << "传入函数之后的结构体值:" << endl;
cout << stu.name << "," << stu.age << "," << stu.score<< endl;
system("pause");
return 0;
}
输出:
引用传递:
#include <iostream>
using namespace std;
struct Student {
string name;
int age;
float score;
};
//值传递
void printStudent(Student* stu) {
stu->name = "jack";
stu->age = 22;
stu->score = 90;
cout << "结构体中的stu信息:" << endl;
cout << stu->name << "," << stu->age << "," << stu->score << endl;
}
int main() {
struct Student stu = { "tom",12,99 };
struct Student* p = &stu;
cout << "未传入函数之前的结构体值:" << endl;
cout << stu.name << "," << stu.age << "," << stu.score << endl;
printStudent(p);
cout << "传入函数之后的结构体值:" << endl;
cout << stu.name << "," << stu.age << "," << stu.score << endl;
system("pause");
return 0;
}
输出:
六、结构体中const的使用场景
作用:用const防止误操作
#include <iostream>
using namespace std;
struct Student {
string name;
int age;
float score;
};
//值传递
void printStudent(const Student* stu) {
/*这里就不能进行修改了
stu->name = "jack";
stu->age = 22;
stu->score = 90;
*/
cout << "结构体中的stu信息:" << endl;
cout << stu->name << "," << stu->age << "," << stu->score << endl;
}
int main() {
struct Student stu = { "tom",12,99 };
struct Student* p = &stu;
cout << "未传入函数之前的结构体值:" << endl;
cout << stu.name << "," << stu.age << "," << stu.score << endl;
printStudent(p);
cout << "传入函数之后的结构体值:" << endl;
cout << stu.name << "," << stu.age << "," << stu.score << endl;
system("pause");
return 0;
}
输出:
只需要记住,用const修饰的数据类型就不能再进行更改。