[C language] encapsulation interface (addition, subtraction, multiplication and division)

Catalog

1、operator.h

2、operator.c

3、 Test entrance

---

1、operator.h

//
// Created by cjs0719 on 2022/6/11.
//

#ifndef TEST_OPERATOR_H
#define TEST_OPERATOR_H

typedef struct {
    double (* Add)(double n, double m);
    double (* Sub)(double n, double m);
    double (* Mul)(double n, double m);
    double (* Div)(double n, double m);
}FAN_OPERATOR;

extern FAN_OPERATOR FanOperator;

void InitOperator(void);

#endif //TEST_OPERATOR_H

2、operator.c

//
// Created by cjs0719 on 2022/6/11.
//

#include "operator.h"
#include <stdio.h>
#include <stdlib.h>

static double add(double n, double m)
{
    return m + n;
}

static double sub(double n, double m)
{
    return n - m;
}

static double mul(double n, double m)
{
    return n * m;
}

static double divnum(double n, double m)
{
    if(m == 0)
    {
        printf(" The divisor cannot be zero 0,m=%f",m);
        return 0.0;
    }
    return n/m;
}

void InitOperator(void)
{
    FanOperator.Add = add;
    FanOperator.Sub = sub;
    FanOperator.Mul = mul;
    FanOperator.Div = divnum;
}

3、 Test entrance

#include <stdio.h>
#include "operator.h"

FAN_OPERATOR FanOperator;

int main() {
    InitOperator();

    double addnum = FanOperator.Add(23,56);
    printf("addnum:%.2f\n",addnum);

    double subnum = FanOperator.Sub(12,23);
    printf("subnum:%.2f\n",subnum);

    double mulnum = FanOperator.Mul(20,30);
    printf("mulnum:%.2f\n",mulnum);

    double divnum = FanOperator.Div(24,3);
    printf("divnum:%.2f\n",divnum);
    return 0;
}

The output shows ：