定义结构（圆）的问题

Question

所以这是问题所在：用场的半径定义圆结构，用场的长度定义方形结构。创建一个接受void *类型指示符和整数参数作为参数的函数。如果其值为0，则指针指示圆型结构，否则指示方形型结构。该函数将指针显示的结构的字段的值增加5，然后返回指针。编写一个控制该功能操作的程序。

这是我的代码：

#include <stdio.h>
struct circle{
    float radius;

};

struct square{
    float side;
    float len;
};

void* resize(void *shape, int type);
int main(void){
    circle *p1, c = {2.45};
    square *p2, s ={4};
    p1 = (circle*)resize(&c, 0); //Error in circle
    p2 = (square*)resize(&s, 1); //Error in square
    printf("%f %d\n", p1->radius, p2 ->len);
    return 0;
}

void* resize(void *shape, int type)
{
    if(type ==0)
        ((circle*)shape)->radius +=5;//Error in circle
    else
        ((square*)shape)->len +=5; //Error in square
    return shape;
}
enter code here

而且我有错误。有人知道如何解决吗？错误是：

E:\TDM-GCC\bin\untitled5\main.c: In function 'main':
E:\TDM-GCC\bin\untitled5\main.c:14:5: error: unknown type name 'circle'; use 'struct' keyword to refer to the type
     circle *p1, c = {2.45};
     ^~~~~~
     struct 
E:\TDM-GCC\bin\untitled5\main.c:15:5: error: unknown type name 'square'; use 'struct' keyword to refer to the type
     square *p2, s ={4};
     ^~~~~~
     struct 
E:\TDM-GCC\bin\untitled5\main.c:16:11: error: 'circle' undeclared (first use in this function)
     p1 = (circle*)resize(&c, 0);
           ^~~~~~
E:\TDM-GCC\bin\untitled5\main.c:16:11: note: each undeclared identifier is reported only once for each function it appears in
E:\TDM-GCC\bin\untitled5\main.c:16:18: error: expected expression before ')' token
     p1 = (circle*)resize(&c, 0);
                  ^
E:\TDM-GCC\bin\untitled5\main.c:17:11: error: 'square' undeclared (first use in this function)
     p2 = (square*)resize(&s, 1);
           ^~~~~~
E:\TDM-GCC\bin\untitled5\main.c:17:18: error: expected expression before ')' token
     p2 = (square*)resize(&s, 1);
                  ^
E:\TDM-GCC\bin\untitled5\main.c:18:25: error: request for member 'radius' in something not a structure or union
     printf("%f %d\n", p1->radius, p2 ->len);
                         ^~
E:\TDM-GCC\bin\untitled5\main.c:18:38: error: request for member 'len' in something not a structure or union
     printf("%f %d\n", p1->radius, p2 ->len);
                                      ^~
E:\TDM-GCC\bin\untitled5\main.c: In function 'resize':
E:\TDM-GCC\bin\untitled5\main.c:25:11: error: 'circle' undeclared (first use in this function)
         ((circle*)shape)->radius +=5;
           ^~~~~~
E:\TDM-GCC\bin\untitled5\main.c:25:18: error: expected expression before ')' token
         ((circle*)shape)->radius +=5;
                  ^
E:\TDM-GCC\bin\untitled5\main.c:27:11: error: 'square' undeclared (first use in this function)
         ((square*)shape)->len +=5;
           ^~~~~~
E:\TDM-GCC\bin\untitled5\main.c:27:18: error: expected expression before ')' token
         ((square*)shape)->len +=5;
                  ^
mingw32-make.exe[3]: *** [CMakeFiles\untitled5.dir\build.make:62: CMakeFiles/untitled5.dir/main.c.obj] Error 1
mingw32-make.exe[2]: *** [CMakeFiles\Makefile2:75: CMakeFiles/untitled5.dir/all] Error 2
mingw32-make.exe[1]: *** [CMakeFiles\Makefile2:82: CMakeFiles/untitled5.dir/rule] Error 2
mingw32-make.exe: *** [Makefile:117: untitled5] Error 2

Answer 1

您不能使用'circle'，您不能使用其他结构。

您需要使用'结构圈'等。>>

如果您不想使用“结构圈”，可以这样做：

typedef struct circle{
    float radius;
} Circle;
并且只使用'Circle'