#include "stdio.h"
main ()
{
 char sex,sports,diet;
 double faheight,moheight,height;
printf("请输入性别，男性为：M，女性为：F  ：");
scanf("%c",&sex);
if(sex=='M')  printf ("体育锻炼，喜爱：Y，不喜爱：N :");
 scanf("%c",&sports);
 if(sports=='Y') printf("饮食习惯，良好：Y，不好：N :");
 scanf("%c",&diet);
 if(diet=='Y') printf("父亲身高：，母亲身高:");
 scanf("%lf%lf",&faheight,&moheight);
 height=(faheight+moheight)*0.54*1.035;
 printf("成人身高=%lf\n",&height);
 else (diet=='N') printf("父亲身高：，母亲身高:");
 scanf("%lf%lf",&faheight,&moheight);
 height=(faheight+moheight)*0.54*1.02;
 printf("成人身高=%lf\n",height);
 else (sports=='N') printf("父亲身高：，母亲身高:");
 scanf("%lf%lf",&faheight,&moheight);
 height=(faheight+moheight)*0.54;
 printf("成人身高=%lf\n",height");
else (sex=='F') printf ("体育锻炼，喜爱：Y，不喜爱：N :")；
 scanf("%c",&sports);
 if(sports=='Y') printf("饮食习惯，良好：Y，不好：N :");
 scanf("%c",&diet);
 if(diet=='Y')  printf("父亲身高：，母亲身高:");
 scanf("%lf%lf",&faheight,&moheight);
 height=(faheight*0.923+moheight)*0.54*1.035;
 printf("成人身高=%lf\n",height);
 else (diet=='N') printf("父亲身高：，母亲身高:");
 scanf("%lf%lf",&faheight,&moheight);
 height=(faheight*0.923+moheight)*0.54*1.02;
 printf("成人身高=%lf\n",height);
 else (sports=='N') printf("父亲身高：，母亲身高:");
 scanf("%lf%lf",&faheight,&moheight);
 height=(faheight*0.923+moheight)*0.54;
 printf("成人身高=%lf\n",height);
}

这题有点恶心。最好的方法是先输入数据，然后再逐层判断，这样会清晰的多。
#include "stdio.h"
int main ()
{
    char sex,sports,diet;
    double faheight,moheight,height;
   //输入数据：
    printf("请输入性别，男性为：M，女性为：F  ：");
        scanf("%c",&sex);
        getchar();
    printf ("体育锻炼，喜爱：Y，不喜爱：N :");
        scanf("%c",&sports);
        getchar();
    printf("饮食习惯，良好：Y，不好：N :");
        scanf("%c",&diet);   
        getchar();            
    printf("父亲身高：，母亲身高:");
        scanf("%lf%lf",&faheight,&moheight);
    //计算处理：
    if(sex=='M')  
        if(sports=='Y')
            if(diet=='Y') height=(faheight+moheight)*0.54*1.035;
            else  height=(faheight+moheight)*0.54*1.02;
        else  height=(faheight+moheight)*0.54;
    else
        if(sports=='Y')
            if(diet=='Y') height=(faheight*0.923+moheight)*0.54*1.035;
            else  height=(faheight*0.923+moheight)*0.54*1.02;
        else height=(faheight*0.923+moheight)*0.54;

   //输出结果：
    printf("成人身高=%lf\n",height);

    return 0;

}

大哥，我的具体错在哪里，能帮我画出来吗？谢谢

主要问题是：if语句管辖多个语句时，不知用大花括号括起来。另外：整个思路太乱了，没有条理。

甚至有些 条件前没有 if

只是在你的程序上，添加了适当的括号和if关键字，你自己对照一下：
#include<stdio.h>
int main ()
{
    char sex,sports,diet;
    double faheight,moheight,height;

    printf("请输入性别，男性为：M，女性为：F  ：");
    scanf("%c",&sex);

    if(sex=='M')
    {
        printf ("体育锻炼，喜爱：Y，不喜爱：N :");   
        scanf("%c",&sports);
        if(sports=='Y')
        {
            printf("饮食习惯，良好：Y，不好：N :");
            scanf("%c",&diet);
            if(diet=='Y')
            {
                printf("父亲身高：，母亲身高:");
                scanf("%lf%lf",&faheight,&moheight);
                height=(faheight+moheight)*0.54*1.035;
                printf("成人身高=%lf\n",&height);
            }
            else if    (diet=='N')
            {
                printf("父亲身高：，母亲身高:");
                scanf("%lf%lf",&faheight,&moheight);
                height=(faheight+moheight)*0.54*1.02;
                printf("成人身高=%lf\n",height);
            }
        }
        else if(sports=='N')
        {
            printf("父亲身高：，母亲身高:");
            scanf("%lf%lf",&faheight,&moheight);
            height=(faheight+moheight)*0.54;
            printf("成人身高=%lf\n",height);
        }
    }
    else if (sex=='F')
    {
        printf ("体育锻炼，喜爱：Y，不喜爱：N :");
        scanf("%c",&sports);
        if(sports=='Y')
        {
            printf("饮食习惯，良好：Y，不好：N :");
            scanf("%c",&diet);
            if(diet=='Y')
            {
                printf("父亲身高：，母亲身高:");
                scanf("%lf%lf",&faheight,&moheight);
                height=(faheight*0.923+moheight)*0.54*1.035;
                printf("成人身高=%lf\n",height);
            }
            else if (diet=='N')
            {
                printf("父亲身高：，母亲身高:");
                scanf("%lf%lf",&faheight,&moheight);
                height=(faheight*0.923+moheight)*0.54*1.02;
                printf("成人身高=%lf\n",height);
            }
        }
        else if (sports=='N')
        {
            printf("父亲身高：，母亲身高:");
            scanf("%lf%lf",&faheight,&moheight);
            height=(faheight*0.923+moheight)*0.54;
            printf("成人身高=%lf\n",height);
        }
    }
    return 0;
}

刚刚起步，见笑了。一定努力改正！！

else没有对应的IF吧

忘了加某些东西吧。当确认性别后就会结束程序了。

对啊，怎么破
？