Java - 根据用户的回答询问问题 x 次

Question

我想根据答案问三个问题 x 次，然后我想根据给出的答案计算总成本。我想知道这种方式是否有效，如果有效，我如何计算总成本？

public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    System.out.println("x ingredients?");
    int amount = sc.nextInt();

    for(int i = 1 ; i <= amount; i++) { 
        System.out.print("Nr " + i + ": How much do you have?\n");
        int have = sc.nextInt();
        System.out.print("Nr " + i + ": How much do you need?\n");
        int need = sc.nextInt();
        System.out.print("Nr " + i + ": How much does it cost?");
        int cost = sc.nextInt();
        if(i == amount) {
            // calculate total cost 
        }
    }   
}

Answer 1

您需要跟踪循环外的总成本，否则它将超出范围。例如，在循环之前，初始化总成本:

int totalCost = 0; //you used sc.nextInt() so I assume no decimals

然后，在循环中，只需获取购买数量并乘以成本即可。

int toBuy = need - have;
//you do NOT need if (i == amount) because you will add to the cost whenever it's necessary, not just at the end of the loop
if (toBuy > 0){ //don't buy things you don't need
    totalCost += toBuy * cost;
}

然后，在循环外打印总成本:

for (int i = 1; i <= amount; i++){
    //...
}
System.out.println("Total cost of ingredients: " + totalCost);