#include 

int main(){
    double item1, item2, cheaper, discount, total;

    // 输入两个商品的价格
    printf("Enter the price of item 1: ");
    scanf("%lf", &item1);
    printf("Enter the price of item 2: ");
    scanf("%lf", &item2);

    // 确定哪个商品更便宜
    if(item1 < item2){
        cheaper = item1;
    } else {
        cheaper = item2;
    }

    // 根据价格打折
    if(cheaper <= 10){
        discount = cheaper * 0.1;
    } else {
        discount = cheaper * 0.2;
    }

    // 计算总价
    total = item1 + item2 - discount;

    // 输出结果
    printf("Total expenses after applying discount: $%.2lf", total);

    return 0;
}

运行示例：

Enter the price of item 1: 8.99
Enter the price of item 2: 12.49
Total expenses after applying discount: $19.19