#include <stdio.h>
int main()
{
    int g;
    scanf("%d",&g);
    float f,m,t,r;
    printf("boy=1,girl=2");
    printf("father:");
    scanf("%f",&f);
    printf("mother:");
    scanf("%f",&m);
    if (g==1)
        t=(f+m)*1.08/2;
    else if (g==2)
        t=(f*0.923+m)/2;
        printf("%.0f\n",t);
    else  
        printf("gender error\n");
    printf(":\n");
    scanf("%f",&r);
    if ((t-r)<=3&&(t-r)>=-3)
    {
        printf("coincident\n");
    }
    else
            printf("incoincident\n");
    }

    if (g==1)
        t=(f+m)*1.08/2;
    else if (g==2)//这里少了花括号，导致下面的else悬挂
        t=(f*0.923+m)/2;
        printf("%.0f\n",t); 
    else  
        printf("gender error\n");

嗯嗯，万分感谢

#include <stdio.h>
int main()
{
    int g;
    scanf("%d",&g);
    float f,m,t,r;
    printf("select gender:boy=1,girl=2\n");
    printf("father:");
    scanf("%f",&f);
    printf("mother:");
    scanf("%f",&m);
    if (g==1)
    {
        t=(f+m)*1.08/2;
        printf("%.0f\n",t);
    }
    else if (g==2)
    {
        t=(f*0.923+m)/2;
        printf("%.0f\n",t);
    }
    else  
        printf("gender error\n");
    printf("your real height:\n");
    scanf("%f",&r);
    if ((t-r)<=3&&(t-r)>=-3)
    {
        printf("coincident\n");
    }
    else
            printf("incoincident\n");
    }
好吧，刚刚还有其他的错误，现在改好了，渴望有大佬提点

#include <stdio.h>
int main()
{
    int g;
    scanf("%d",&g);
    float f,m,t,r;
    printf("boy=1,girl=2");
    printf("father:");
    scanf("%f",&f);
    printf("mother:");
    scanf("%f",&m);
    if (g==1)
        t=(f+m)*1.08/2;
    else if (g==2)
        {                               //这里是两句话要加括号
         t=(f*0.923+m)/2;
        printf("%.0f\n",t);
        }

    else
        printf("gender error\n");       //不加括号只执行一句话，所以下面这个换行不是else语句里面的
    printf(":\n");
    scanf("%f",&r);
    if ((t-r)<=3&&(t-r)>=-3)
        printf("coincident\n");             //这种下面只有一句话不要括号就可以了
    else
            printf("incoincident\n");
    }

嗯，谢谢