#include<stdio.h>
int main(void)
{
int price;
printf("定価＝");
scanf("%d",&price);
printf("一割引＝%d\n",(int)(price*0.9));
priotf("三割引＝%d\n",(int)(price*0.7));
priotf("五割引＝%d\n",(int)(price*0.5));
priotf("八割引＝%d\n",(int)(price*0.2));
return 0;
}
これでいいかな？