C :

#include<stdio.h>
 
/**
 *
 * @param weight 物品总重量
 * @param baseWeight 首重
 * @param addionalWeight 续重
 */
void getBaseWeightAndAddionalWeight(const int weight, float *baseWeight,float *addionalWeight){
    if (weight >= 1) {
        *baseWeight = 1;
        *addionalWeight = (int)(weight - *baseWeight + 1) * 1.0;
    } else {
        *baseWeight = 1;
        *addionalWeight = 0;
    }
}
int main() {
    float baseWeight;
    float addionalWeight;
    float weight;
    int area;
    scanf("%d,%f", &area, &weight);
    if (area < 0 || area > 4) {
        printf("Error in Area\n");
    }
    getBaseWeightAndAddionalWeight(weight, &baseWeight, &addionalWeight);
    float price = 0;
    switch (area) {
        case 0:
            price = 10 * baseWeight + 3 * addionalWeight;
            break;
        case 1:
            price = 10 * baseWeight + 4 * addionalWeight;
            break;
        case 2:
            price = 15 * baseWeight + 5 * addionalWeight;
            break;
        case 3:
            price = 15 * baseWeight + 6.5 * addionalWeight;
            break;
        case 4:
            price = 15 * baseWeight + 10 * addionalWeight;
            break;
    }
    printf("Price: %5.2f\n", price);
    return 0;
}