玩宏

Question

在“区域”内

    #include <math.h>
        
    extern double peri;
    extern double area;
        
    #define AREA_C(x) (x*x* M_PI)
    #define PERI_C(x) (x*2*M_PI)
    
    #define PERI(length, depth, polygone){\
                if((polygone == "square")||(polygone == "rectangle"))\
                    peri = length * 2 + depth * 2;\
    }
    
    #define AREA(a,b,polygone){\
                if((polygone == "square")||(polygone == "rectangle"))\
                    area = a * b;\
                else if(polygone == "triangle")\
                    area = a * b / 2;\
    }

在“区域”内

    #include "areaperi.h"
    #include <stdio.h>
    
    
    int main(){
        double Carea = AREA_C(3);
        double Cperi = PERI_C(3);
        printf("area: %.2lf\n", Carea);
        printf("peri: %.2lf\n", Cperi);
        AREA(2,2,"square");
        printf("%.2lf\n", area);
    
        return 0;
    }

嗨，试着玩宏和存储类。但我面临一个错误。这段代码不是为了提高效率，它只是一个练习。

误差

areaperi.h:14:28:警告:反斜杠-文件末尾的换行符#定义区域(a，b，polygone){\

C:\Users\elena\AppData\Local\Temp\ccyOjbOH.o:areaperi.c:(.text+0x52)：未定义的对area' C:\Users\elena\AppData\Local\Temp\ccyOjbOH.o:areaperi.c:(.text+0x58): undefined reference to区域的收藏品2.exe的引用:错误: ld返回1退出状态

Answer 1

头文件

#include <math.h>

extern double peri;
extern double area;

#define AREA_C(x) (x*x* M_PI)
#define PERI_C(x) (x*2*M_PI)

#define PERI(length, depth, polygone){\
            if((polygone == "square")||(polygone == "rectangle"))\
                peri = length * 2 + depth * 2;\
}

#define AREA(a,b,poly){\
            if((poly == "square")||(poly == "rectangle"))\
                area = a * b;\
            else if(poly == "triangle")\
                area = a * b / 2;\
                puts("");\
}

file.c

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

double area;
double peri;

int main(){
    double Carea = AREA_C(3);
    double Cperi = PERI_C(3);
    printf("area: %.2lf\n", Carea);
    printf("peri: %.2lf\n", Cperi);
    AREA(2,2,"square");
    printf("Area of the square: %.2lf\n", area);

    return 0;
}

误差

在定义了变量之后，消除了主要错误，但是仍然存在"24: warning: backslash-newline at end of file"，使用该变量，我只添加了puts("");并修复了它。

如果想了解更多关于该错误的信息，我可以在以下网站找到答案：this stock overflow page