struct的精确用法

我终于回来啦！

1,可以创造根据结构体格式的成员或数组。

普通成员

数组成员

2,可以用指针遍历成员

3,使用typedef

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今天我整理了一些struct的用法，但我先说一声：

我终于回来啦！

前几天一直没空，因为今天有空，所以今天更新一下。那么首先第一个用法是：

1,可以创造根据结构体格式的成员或数组。

普通成员

我们先看下列例子：

#include <stdio.h>
#include<iostream>
struct student
{char name[20];int age;char sex[7];int score;
};student stu1 = {"Wang.x.m",12,"boy",90};
int main(){std::cout<<stu1.name<<" "<<stu1.age<<" "<<stu1.sex<<" "<<stu1.score;
}

这个代码很简单，首先创造一个经典结构体struct，然后在结构体里创建了变量name,age,sex和,score，之后创建一个结构体成员，最后打印。

运行结果：

数组成员

但是如果成员有10个，那么根据前面的就只能这么写：

#include <stdio.h>
#include <iostream>
struct student
{char name[20];int age;char sex[7];int score;
};
int main()
{student stu1 = {"Wang.x.m", 12, "boy", 90};student stu2 = {"Li.y.n", 13, "girl", 85};student stu3 = {"Zhang.z.o", 11, "boy", 92};student stu4 = {"Chen.a.p", 14, "boy", 88};student stu5 = {"Liu.b.q", 12, "girl", 91};student stu6 = {"Sun.c.r", 13, "boy", 87};student stu7 = {"Zhao.d.s", 11, "girl", 93};student stu8 = {"Wu.e.t", 14, "boy", 86};student stu9 = {"Zhou.f.u", 12, "girl", 94};student stu10 = {"Qian.g.v", 13, "boy", 89};std::cout << stu1.name << " " << stu1.age << " " << stu1.sex << " " << stu1.score << std::endl;std::cout << stu2.name << " " << stu2.age << " " << stu2.sex << " " << stu2.score << std::endl;std::cout << stu3.name << " " << stu3.age << " " << stu3.sex << " " << stu3.score << std::endl;std::cout << stu4.name << " " << stu4.age << " " << stu4.sex << " " << stu4.score << std::endl;std::cout << stu5.name << " " << stu5.age << " " << stu5.sex << " " << stu5.score << std::endl;std::cout << stu6.name << " " << stu6.age << " " << stu6.sex << " " << stu6.score << std::endl;std::cout << stu7.name << " " << stu7.age << " " << stu7.sex << " " << stu7.score << std::endl;std::cout << stu8.name << " " << stu8.age << " " << stu8.sex << " " << stu8.score << std::endl;std::cout << stu9.name << " " << stu9.age << " " << stu9.sex << " " << stu9.score << std::endl;std::cout << stu10.name << " " << stu10.age << " " << stu10.sex << " " << stu10.score << std::endl;return 0;
}

这种代码十分不整洁，既不好看还效率低，这时候我们可以运用数组：

#include <stdio.h>
#include <iostream>
struct student
{char name[20];int age;char sex[7];int score;
};
int main()
{student students[10] = {{"Wang.x.m", 12, "boy", 90},{"Li.y.n", 13, "girl", 85},{"Zhang.z.o", 11, "boy", 92},{"Chen.a.p", 14, "boy", 88},{"Liu.b.q", 12, "girl", 91},{"Sun.c.r", 13, "boy", 87},{"Zhao.d.s", 11, "girl", 93},{"Wu.e.t", 14, "boy", 86},{"Zhou.f.u", 12, "girl", 94},{"Qian.g.v", 13, "boy", 89}};for (int i = 0; i < 10; i++){std::cout << students[i].name << " " << students[i].age << " " << students[i].sex << " " << students[i].score << std::endl;}return 0;
}

这样就比上一个少了900多个字符。

2,可以用指针遍历成员

但是这样需要0.58秒才能运行，很容易让我们等死，如果你想让运行得快一点，那么可以运用指针：

#include <stdio.h>
#include <iostream>
struct student
{char name[20];int age;char sex[7];int score;
};
int main()
{student students[10] = {{"Wang.x.m", 12, "boy", 90},{"Li.y.n", 13, "girl", 85},{"Zhang.z.o", 11, "boy", 92},{"Chen.a.p", 14, "boy", 88},{"Liu.b.q", 12, "girl", 91},{"Sun.c.r", 13, "boy", 87},{"Zhao.d.s", 11, "girl", 93},{"Wu.e.t", 14, "boy", 86},{"Zhou.f.u", 12, "girl", 94},{"Qian.g.v", 13, "boy", 89}};student* ptr = students;for (int i = 0; i < 10; i++){std::cout << ptr->name << ptr->age << ptr->sex << ptr->score;ptr++;}return 0;
}

3,使用typedef

但这样比之前也快了0.05秒。有没有更快的方法呢？有，使用typedef关键词，比如这样：

#include <stdio.h>
struct student
{char name[20];int age;char sex[7];int score;
};
typedef student Stu;
int main()
{Stu students[10] = {{"Wang.x.m", 12, "boy", 90},{"Li.y.n", 13, "girl", 85},{"Zhang.z.o", 11, "boy", 92},{"Chen.a.p", 14, "boy", 88},{"Liu.b.q", 12, "girl", 91},{"Sun.c.r", 13, "boy", 87},{"Zhao.d.s", 11, "girl", 93},{"Wu.e.t", 14, "boy", 86},{"Zhou.f.u", 12, "girl", 94},{"Qian.g.v", 13, "boy", 89}};Stu* ptr = students;for (int i = 0; i < 10; i++){printf("%s %d %s %d\n", ptr->name, ptr->age, ptr->sex, ptr->score);ptr++;}return 0;
}

这样写可以直接把运行速度飙升到：

4.格式环节

结构体创造：

struct 结构体名{格式1格式2格式3...格式n
};

成员创造：

普通成员：

struct 结构体名 结构体成员名 = {结构体变量1,结构体变量2,结构体变量3・・・结构体变量n};

数组成员：

struct 结构体名 结构体成员[n]={{结构体变量1.1,结构体变量1.2,结构体变量1.3···结构体成员1.n},{结构体变量2.1,结构体变量2.2,结构体变量2.3···结构体成员2.n},{结构体变量3.1,结构体变量3.2,结构体变量3.3···结构体成员3.n},...{结构体变量n.1,结构体变量n.2,结构体变量n.3···结构体成员n.n}};