Question

我在C编码方面相当新。我正在尝试让下面的项目运行，但它说我的程序在输入第三个输入后停止工作。我不相信我选择使用带有全部或布尔值的while循环是接近这个的正确选择。我几乎觉得应该在某个地方添加一个if / else语句。

我已经为项目提供了基本上沿着这些方向的流程图：

获取inv1-4的输入值

代码！= - 1

如果代码是！= 1继续循环并获取金额的输入值   买/卖

否则打印inv1-4

#include <stdio.h>

int main(void)

{
    int inv1;
    int inv2;
    int inv3;
    int inv4;
    int amount_purchased;
    int amount_sold;

    printf("Please provide beginning inventory amounts in cases between 1 and 4.\n\n");
    printf("Enter the number of inventory for Piels (ID number 1): ");
    scanf("%d", &inv1);

    printf("\nEnter the number of inventory for Coors (ID number 2): ");
    scanf("%d", &inv2);

    printf("\nEnter the number of inventory for Bud (ID number 3): ");
    scanf("%d", &inv3);

    printf("\nEnter the number of inventory for Iron City (ID number 4): ");
    scanf("%d", &
          inv4);


    while (inv1 != -1 && inv2 != -1 && inv3 != -1 && inv4 != -1) {
            printf("\nEnter the number of cases of Piels (ID 1) purchased and sold this week.\n");
            printf("Amount purchased: \n");
            scanf("%d", &amount_purchased);
            printf("Amount sold: \n");
            scanf("%d", &amount_sold);
            inv1 = inv1 + amount_purchased - amount_sold;

            printf("\nEnter the number of cases of Coors (ID 2) purchased and sold this week.\n");
            printf("Amount purchased: \n");
            scanf("%d", &amount_purchased);
            printf("Amount sold: \n");
            scanf("%d", &amount_sold);
            inv2 = inv2 + amount_purchased - amount_sold;

            printf("\nEnter the number of cases of Bud (ID 3)purchased and sold this week.\n");
            printf("Amount purchased: \n");
            scanf("%d", &amount_purchased);
            printf("Amount sold: \n");
            scanf("%d", &amount_sold);
            inv3 = inv3 + amount_purchased - amount_sold;

            printf("\nEnter the number of cases of Iron City (ID 4) purchased and sold this week.\n");
            printf("Amount purchased: \n");
            scanf("%d", &amount_purchased);
            printf("Amount sold: \n");
            scanf("%d", &amount_sold);
            inv4 = inv4 + amount_purchased - amount_sold;



    }

    printf("Ending inventory is as follows.\n\n");

    printf("Piels (ID Number 1): %d \n", inv1);
    printf("Coors (ID Number 2): %d \n", inv2);
    printf("Bud (ID Number 3): %d \n", inv3);
    printf("Iron City (ID Number 4): %d \n", inv4);

    return 0;

}

Answer 1

我猜这个问题

while (inv1 || inv2 || inv3 || inv4 != -1)

你写的不是你所期望的。 (inv1 || inv2 || inv3 || inv4 != -1)在何时评估为true inv1不是0，或 inv2不是0，或 inv3不是0，或 inv4 不是-1。你可能想要的是这些变量中的任何一个为-1，循环必须结束。在这种情况下，正确的条件是：

while(inv2 != -1 && inv2 != -1 && inv3 != -1 && inv4 != -1)
{
    ...
}

请注意，在布尔代数中a && b相当于!a || !b。 a || b 相当于!a && !b。

您的scanf也是错误的，因为很多人在评论中写道。你必须将指针传递给int，而不是int。而不是

scanf("%d", amount_sold);

应该是

scanf("%d", &amount_sold);

这适用于您的所有scanf次来电，否则就是未定义的行为并且未定义行为的结果是未定义的。

修改

我刚注意到你在循环结束时有一个无条件的break。如果你是在第一次迭代中离开循环，为什么要循环首先？或者你忘了添加一些if(condition) break？

Answer 2

您有一些基本的语法问题，例如

scanf("%d", &inv1)

而不是

scanf("%d", inv1)

while循环语法也是错误的。

while(inv2 != -1 && inv2 != -1 && inv3 != -1 && inv4 != -1)

而不是

while (inv1 || inv2 || inv3 || inv4 != -1)

另一个逻辑问题。 while循环将运行一次。因为你在循环结束时编写了“break”语句。所以根本不需要任何循环。只写无循环

printf("\nEnter the number of cases of Piels (ID 1) purchased and sold this week.\n");
        printf("Amount purchased: \n");
        scanf("%d", &amount_purchased);
        printf("Amount sold: \n");
        scanf("%d", &amount_sold);
        inv1 = inv1 + amount_purchased - amount_sold;

        printf("\nEnter the number of cases of Coors (ID 2) purchased and sold this week.\n");
        printf("Amount purchased: \n");
        scanf("%d", &amount_purchased);
        printf("Amount sold: \n");
        scanf("%d", &amount_sold);
        inv2 = inv2 + amount_purchased - amount_sold;

        printf("\nEnter the number of cases of Bud (ID 3)purchased and sold this week.\n");
        printf("Amount purchased: \n");
        scanf("%d", &amount_purchased);
        printf("Amount sold: \n");
        scanf("%d", &amount_sold);
        inv3 = inv3 + amount_purchased - amount_sold;

        printf("\nEnter the number of cases of Iron City (ID 4) purchased and sold this week.\n");
        printf("Amount purchased: \n");
        scanf("%d", &amount_purchased);
        printf("Amount sold: \n");
        scanf("%d", &amount_sold);
        inv4 = inv4 + amount_purchased - amount_sold;

如果你打算这样做，它将会起作用。

C循环问题

2 个答案: