#include "stdio.h"
typedef.struct
{
    float read,imag;
}complex;
 complex sub(complex fs1,complex fs2)
{
    complex fs3;
    fs3.read=fs1.read-fs2.read;
    fs3.imag=fs1.imag-fs2.imag;
    return fs3;
}

main()
{
    complex fs1,,fs2,fs3;
    float a,b,c,d;
    printf("输入复数FS1实虚部：、\n");
        scanf("%f%f",&a,&b);
    fs1.read=a;
    fs1.imag=b;
    printf("输入复数FS2实虚部：\n");
    scanf("%f%f',&c,&d);
        fs2.read=c;
    fs2.imag=d;
    printf("所输入的两复数分别为：\n");
    printf("fs1=%f+%fi",fs1.read,fs2.imag);
    printf("fs2=%f+%fi",fs2.read,fs2.imag);
    fs3=sub(fs1,fs2);
    printf("fs3=fs1-fs2=%f+%fi",fs3.read,fs3.imag);
}

高手帮忙看一下！谢谢！

complex fs1,,fs2,fs3;

那个是我发帖时写错的，编译后检查时提示是红色处出错误，但我不知怎么个错法……
#include "stdio.h"
typedef.struct
{
    float read,imag;
}complex;
complex sub(complex fs1,complex fs2)
{
    complex fs3;
    fs3.read=fs1.read-fs2.read;
    fs3.imag=fs1.imag-fs2.imag;
    return fs3;
}

main()
{
    complex fs1,,fs2,fs3;
    float a,b,c,d;
    printf("输入复数FS1实虚部：、\n");
        scanf("%f%f",&a,&b);
    fs1.read=a;
    fs1.imag=b;
    printf("输入复数FS2实虚部：\n");
    scanf("%f%f',&c,&d);
        fs2.read=c;
    fs2.imag=d;
    printf("所输入的两复数分别为：\n");
    printf("fs1=%f+%fi",fs1.read,fs2.imag);
    printf("fs2=%f+%fi",fs2.read,fs2.imag);
    fs3=sub(fs1,fs2);
    printf("fs3=fs1-fs2=%f+%fi",fs3.read,fs3.imag);
}

#include "stdio.h"
typedef struct//改动1多了个点
{
    float read,imag;
}complex;
complex sub(complex fs1,complex fs2)
{
    complex fs3;
    fs3.read=fs1.read-fs2.read;
    fs3.imag=fs1.imag-fs2.imag;
    return fs3;
}

main()
{
    complex fs1,fs2,fs3;//多打个逗号
    float a,b,c,d;
    printf("输入复数FS1实虚部：、\n");
        scanf("%f%f",&a,&b);
    fs1.read=a;
    fs1.imag=b;
    printf("输入复数FS2实虚部：\n");
    scanf("%f%f",&c,&d);//右边单引号改成双引号
        fs2.read=c;
    fs2.imag=d;
    printf("所输入的两复数分别为：\n");
    printf("fs1=%f+%fi",fs1.read,fs2.imag);
    printf("fs2=%f+%fi",fs2.read,fs2.imag);
    fs3=sub(fs1,fs2);
    printf("fs3=fs1-fs2=%f+%fi",fs3.read,fs3.imag);
}

这些都是低级错误啊！楼主好好看看给你改好了

typedef struct complex
{
    double x;  
    double y;  
}complexx,*complex_huali;
///////////////获取复数/////////////
void create_complex(double a,double b,complex_huali *f)
{
    *f=(complex_huali)malloc(sizeof(complexx));
    (*f)->x=a;
    (*f)->y=b;
    //printf("输入实部和虚部：\n");
    //scanf("%lf %lf",&(*f)->x,&(*f)->y);
}
///////////////复数加法/////////////
void complex_add(complex_huali *f1,complexx f2,complex_huali *f3)
{
    *f3=(complex_huali)malloc(sizeof(complexx));
    (*f3)->x=(*f1)->x+f2.x;
    (*f3)->y=(*f1)->y+f2.y;
}

    //加法
    complex_add(&f1,*f2,&f3);
    printf("相加等于(%lf)+(%lf)i\n",(*f3).x,(*f3).y);

    complex_huali f1,f2,f3;
    f1=(complex_huali)malloc(sizeof(complexx));
    f2=(complex_huali)malloc(sizeof(complexx));
    f3=(complex_huali)malloc(sizeof(complexx));
    //构造一个复数
    printf("计算复数1+2i和3+4i的加减乘除：\n");
    create_complex(1,2,&f1);  //
    create_complex(3,4,&f2);  //
    //或者直接赋值，必须先对f1,f2,f3开辟内存空间
    f1->x=1;
    f1->y=2;
    f2->x=3;
    f2->y=4;
    //加法
    complex_add(&f1,*f2,&f3);
    printf("相加等于(%lf)+(%lf)i\n",(*f3).x,(*f3).y);

#include "stdio.h"
#include"stdlib.h"
typedef struct
{
    float read,imag;
}complex;
complex sub(complex fs1,complex fs2)
{
    complex fs3;
    fs3.read=fs1.read-fs2.read;
    fs3.imag=fs1.imag-fs2.imag;
    return fs3;
}

 int main()
{
    complex fs1,fs2,fs3;
    float a,b,c,d;
    printf("输入复数FS1实虚部：\n");
        scanf("%f%f",&a,&b);
    fs1.read=a;
    fs1.imag=b;
    printf("输入复数FS2实虚部：\n");
    scanf("%f%f",&c,&d);
        fs2.read=c;
    fs2.imag=d;
    printf("所输入的两复数分别为：\n");
    printf("fs1=%f+%fi",fs1.read,fs1.imag);
    printf("fs2=%f+%fi",fs2.read,fs2.imag);
    fs3=sub(fs1,fs2);
    if(fs3.imag>0)
    printf("fs3=fs1-fs2=%f+%fi",fs3.read,fs3.imag);
    if(fs3.imag==0)
    printf("fs3=fs1-fs2=%f",fs3.read);
    if(fs3.imag<0)
    printf("fs3=fs1-fs2=%f%fi",fs3.read,fs3.imag);
    if(fs1.read==fs2.read&& fs2.imag==fs1.imag)
    printf("fs3=fs1-fs2=0\n");
     if(fs3.read==0)
    printf("fs3=fs1-fs2=%fi",fs3.imag);
    system("pause");
}

应该没错