学习笔记习题3.3

#include<stdio.h>
#define price 5
int main(){

?? // const int price = 5 ;
??? int shuliang = 0 ;??? ???
??? printf(" 请输入一个数值！");
???
??? scanf("%d" ,&shuliang);

??? if(shuliang >= 20 ){
??? ??? printf("%.2f",(float)shuliang *? 0.9 * price );
??? }else if(shuliang >= 50 ){
??? ??? ??? printf("%.2f",(float)shuliang *? 0.7 * price );
??? }else{
??? ??? ??? printf("%d", shuliang * price );
??? }
??? return 0 ;
}