c - 为什么我的代码不返回任何东西？

Question

假设对于一个条目，例如:

1 1 524 5 true -1

where the first parameter is the idOrder, the second parameter is the number of products in idOrder, the third parameter is a code, the fourth parameter is the amount of products, the fifth parameter is a boolean to distinguish the product and the sixth parameter is the final mark.

It should return an output such as:

524 -1 5

where the first parameter is the code of the product, the second parameter is the final mark and the third parameter is the amount of products.

This is my code:

#include <stdio.h>

typedef enum {false, true} bool;

int main()
{
    const int END = -1;

    int idOrder, numProducts, idCodeProduct, amount, total, temp;
    bool generic, endSeq;

    scanf("%d", temp);
    /*printf("%d ", temp);*/
    idOrder = temp;
    endSeq = temp == END;

    if (endSeq != true) {
        total = 0;
        scanf("%d", &temp);
        numProducts = temp;
        scanf("%d", &temp);
        idCodeProduct = temp;
        scanf("%d", &temp);
        amount = temp;
        scanf("%d", &temp);
        generic = temp;

        if (generic == true) {
            total = total + amount;
            printf("%d", idCodeProduct);
        }
    }
    printf("%d ", END);
    printf("%d ", total);
    return 0;
}

当我运行这段代码时，它根本没有返回任何东西，我也不知道为什么。

Answer 1

问题是您在 scanf 的格式代码中有一个尾随空格。虽然这会导致 scanf 读取并丢弃空白，但它也会导致 scanf 读取直到找到非空白。如果没有更多内容可读，scanf 将无限期地等待更多输入。

删除格式中的尾随空格，效果会更好。只要您要扫描普通字符串或数字，就必须记住 scanf 实际上会自动跳过前导空格。

我建议您阅读例如this scanf reference .