gen gongzi=0

if(gongzi_max [`i']!=.&gongzi_min[`i']!=.){
                replace gongzi=(gongzi_max  in `i' + gongzi_min in `i')/2
}
else if(gongzi_max [`i']!=.&gongzi_min[`i']==.){
                 replace gongzi= gongzi_max  in `i'
}
else if(gongzi_max [`i']==.&gongzi_min[`i']!=.){
                replace gongzi= gongzi_min in `i'
}

//系统提示错误？是程序哪里写错了吗？