#include <stdio.h>
int main1()
{
    double sex,high,weight,goodweight;
    printf("请输入您的性别,男=1,女=0,sex= \n");
    scanf("%d\n",&sex);
    printf("请输入您的身高(单位cm),high= \n");
    scanf("%f\n",&high);
    printf("请输入您的体重(单位KG),weight= \n");
    scanf("%f\n",&weight);

    if(sex)      { goodweight = (high-100)*0.9;}
     else         {goodweight = (high-100)*0.9-2.5;}    
    if((weight <= 0.6*goodweight))       
        printf("很遗憾，您已经脱离正常人范围了，请立即去救助站~！");   
    if((weight >= 0.6*goodweight))&&((weight <= 0.8*goodweight))      
        printf("您处于消瘦状态，请增重%dkg，多吃多锻炼",(int)(goodweight-weight+1));  
    if((weight >= 0.8*goodweight))&&((weight <= 0.9*goodweight))      
        printf("您处于偏瘦状态，请增重%dkg，适当锻炼身体",(int)(goodweight-weight+1));  
    if((weight >= 0.9*goodweight))&&((weight <= 1.1*goodweight))      
        printf("恭喜您，您的体重正常，请保持",);  
    if((weight >= 1.3*goodweight))&&((weight <= 1.5*goodweight))     
        printf("您处于偏胖状态，请减轻%dkg，多吃蔬菜少吃肉",(int)(weight-goodweight+1));   
    if((weight >= 1.5*goodweight))&&((weight <= 1.8*goodweight))    
        printf("您处于肥胖状态，请减轻%dkg，只吃蔬菜不吃肉",(int)(weight-goodweight+1));   
    if((weight >= 0.6*goodweight))     
        printf("我对您深表同情。。。");             
   
        getchar();       
        getchar();   
        return 0;
} 




错误    4    error C2143: 语法错误 : 缺少“;”(在“&&”的前面)  

警告    5    warning C4390: “;”: 找到空的受控语句；这是否是有意的?   

错误太多，给你改完了，自己对比一下，没验证运行情况。
#include <stdio.h>
int main()
{
    double sex,high,weight,goodweight;
    printf("请输入您的性别,男=1,女=0,sex= \n");
    scanf("%d\n",&sex);
    printf("请输入您的身高(单位cm),high= \n");
    scanf("%f\n",&high);
    printf("请输入您的体重(单位KG),weight= \n");
    scanf("%f\n",&weight);

    if(sex)      { goodweight = (high-100)*0.9;}
     else         {goodweight = (high-100)*0.9-2.5;}   
    if(weight <= 0.6*goodweight)      
        printf("很遗憾，您已经脱离正常人范围了，请立即去救助站~！");   
    if((weight >= 0.6*goodweight)&&(weight <= 0.8*goodweight))      
        printf("您处于消瘦状态，请增重%dkg，多吃多锻炼",(int)(goodweight-weight+1));  
    if((weight >= 0.8*goodweight)&&(weight <= 0.9*goodweight))      
        printf("您处于偏瘦状态，请增重%dkg，适当锻炼身体",(int)(goodweight-weight+1));  
    if((weight >= 0.9*goodweight)&&(weight <= 1.1*goodweight))      
        printf("恭喜您，您的体重正常，请保持");  
    if((weight >= 1.3*goodweight)&&(weight <= 1.5*goodweight))     
        printf("您处于偏胖状态，请减轻%dkg，多吃蔬菜少吃肉",(int)(weight-goodweight+1));   
    if((weight >= 1.5*goodweight)&&(weight <= 1.8*goodweight))   
        printf("您处于肥胖状态，请减轻%dkg，只吃蔬菜不吃肉",(int)(weight-goodweight+1));   
    if(weight >= 0.6*goodweight)     
        printf("我对您深表同情。。。");            
   
        getchar();      
        getchar();   
        return 0;
}

把从第二个开始的if都改成else if 来加速你的程序

#include <stdio.h>
int main()
{
    double sex,high,weight,goodweight;
    printf("请输入您的性别,男=1,女=0,sex= \n");
    scanf("%d\n",&sex);
    printf("请输入您的身高(单位cm),high= \n");
    scanf("%f\n",&high);
    printf("请输入您的体重(单位KG),weight= \n");
    scanf("%f\n",&weight);

    if(sex)
        {goodweight = (high-100)*0.9;}
   
    else
        {goodweight = (high-100)*0.9-2.5;}
    if(weight <= 0.6*goodweight)
        printf("很遗憾，请珍惜最后的时光~");
    else if((weight >= 0.6*goodweight)&&(weight <= 0.8*goodweight))
        printf("您处于消瘦状态，请增重%dkg，多吃多锻炼",(int)(goodweight-weight+1));
    else if((weight >= 0.8*goodweight)&&(weight <= 0.9*goodweight))
        printf("您处于偏瘦状态，请增重%dkg，适当锻炼身体",(int)(goodweight-weight+1));
    else if((weight >= 0.9*goodweight)&&(weight <= 1.1*goodweight))
        printf("恭喜您，您的体重正常，请保持",);
    else if((weight >= 1.3*goodweight)&&(weight <= 1.5*goodweight))
        printf("您处于偏胖状态，请减轻%dkg，多吃蔬菜少吃肉",(int)(weight-goodweight+1));
    else if((weight >= 1.5*goodweight)&&(weight <= 1.8*goodweight))
        printf("您处于肥胖状态，请减轻%dkg，只吃蔬菜不吃肉",(int)(weight-goodweight+1));
    else if(weight >= 1.8*goodweight)
        printf("我对您深表同情。。。");
     
        getchar();
        getchar();
        return 0;
}

还是不能运行。。
错误    4    error C2059: 语法错误 : “)”      12    work1

你能再细心点吗？

scanf("%f\n",&high);把每个scanf里面的\n删除吧。
else if((weight >= 0.9*goodweight)&&(weight <= 1.1*goodweight))
        printf("恭喜您，您的体重正常，请保持",);  //明显多个逗号

我真粗心。。。

你这句话突然提醒了我，仔细想想，用else if确实能提高运行速度，看来以后要注意自己的代码风格，不仅要实现功能，还要提高代码效率

大有收获（else if确实能提高运行速度），谢谢