如何让c语言使用结构体近似模拟c++中的类

如今统治市场的主流编程语言，如c++，java，大都是面向对象类型的编程语言。

而众所周知，c语言是面向过程的编程语言，但是它拥有一个类似于类的结构，叫做结构体，主要的区别在于结构体无法定义函数。

因此，为了c语言的结构体近似模拟类，我们可以在结构体中定义函数指针。

下面这个例子，是最常用的计算学生分数平均数的c++类模版：

#include <cstdio>
#include <iostream>
#include <cstdlib>#define LINE for (i = 0 ; i < 60 ; i++) {printf("-");}printf("\n");
#define SPACE for (i = 0 ; i < 20 ; i++) printf(" ");using namespace std;class Student
{
public:
double stuAvg(double score[]);
int num;
char name[10];
double score[3];
double average;
};double Student::stuAvg(double score[]){
double sum = 0.0;
double average = 0.0;
for (int i=0 ; i < 3 ; i++)
{
sum += score[i];
}
return average = sum/3;
}int main(void){
Student stu1;
for (int i = 0 ; i < 3 ; i++)
{
scanf("%lf",&stu1.score[i]);
}
stu1.num = 1001;
memset(stu1.name,0,sizeof(stu1.name));
strcat(stu1.name,"Peter");
stu1.average = stu1.stuAvg(stu1.score);//Output Partprintf("NUM");
SPACE;
printf("NAME");
SPACE;
printf("AVERAGE");
printf("\n");
LINE;
printf("%d",stu1.num);
SPACE;
printf("%s",stu1.name);
SPACE;
printf("%.2lf",stu1.average);
printf("\n");
LINE;
return 0;
}

接下来我们使用结构体模拟上例中类的作用：

#include <stdio.h>
#include <stdlib.h> #define LINE for (i = 0 ; i < 60 ; i++) {printf("-");}printf("\n");
#define SPACE for (i = 0 ; i < 20 ; i++) printf(" "); struct Student{
double (*stuAvg)(double score[]);
int num;
char name[10];
double score[3];
double average;
}; double Calc_Avg(double score[]){
int i = 0;
double sum = 0.0;
double average = 0.0;
for (i=0 ; i < 3 ; i++)
{
sum += score[i];
}
return average = sum/3;
} void main(void){
int i = 0;
struct Student stu1;
for (i = 0 ; i < 3 ; i++)
{
scanf("%lf",&stu1.score[i]);
}
stu1.num = 1001;
memset(stu1.name,0,sizeof(stu1.name));
strcat(stu1.name,"Peter");
stu1.stuAvg = Calc_Avg;
stu1.average = stu1.stuAvg(stu1.score); //Ouuput Part printf("NUM");
SPACE;
printf("NAME");
SPACE;
printf("AVERAGE");
printf("\n");
LINE;
printf("%d",stu1.num);
SPACE;
printf("%s",stu1.name);
SPACE;
printf("%.2lf",stu1.average);
printf("\n");
LINE;
return;
}