程序代码：

#include<stdio.h>
#include<stdlib.h>

int main(viod)
{
    double price,discount,new_discount;
    float cost_discount=0.38;
    printf("产品价格 :");
    scanf("%d",&price);//getchar();
    printf("产品折扣 :");
    scanf("%f",&discount);//getchar();
    printf("产品价格是%d,折扣是%.2f,成本折扣是%f.\n",price,discount,discount-cost_discount);
    double profit=price*(discount-cost_discount);
    printf("产品利润是%d:\n",profit);
    printf("产品新折扣是 :");//getchar();
    scanf("%f",&new_discount);
    double profit1=price*(new_discount-cost_discount);
    if(profit>=profit1)
    printf("前数量= %d 数量.\n",profit/profit1);
    else
    printf("亏本.\n");
    system("pause");
    return 0;
}