if 和 else 语句中的某处错误

Question

大部分都可以正常工作，但是，我注意到如果我尝试添加一个负整数，就会发生这种情况：

正确的输出行是： 请输入两个整数：负一+三=二 你的程序打印了这一行： 请输入两个整数：负三=二

我的“printf 否定”if 语句之后的 ifs 出于某种原因没有打印？

#include <stdio.h>

int main(void)  {
    int numOne;
    int numTwo; 
    printf("Please enter two integers:");
    scanf("%d%d", &numOne, &numTwo); 


    if (numOne >= -10 && numOne < 0) {
        printf("negative");    
    }
    if (numOne == 0) {
        printf("zero + ");
    }
    if (numOne == 1) {
        printf("one + ");
    }
    if (numOne == 2) {
        printf("two + ");
    }
    if (numOne == 3) {
        printf("three + ");
    }
    if (numOne == 4) {
        printf("four + ");
    }
    if (numOne == 5) {
        printf("five + ");
    }
    if (numOne == 6) {
        printf("six + ");
    }
    if (numOne == 7) {
        printf("seven + ");
    }
    if (numOne == 8) {
        printf("eight + ");
    }
    if (numOne == 9) {
        printf("nine + ");
    }
    if (numOne == 10) {
        printf("ten + ");
    } else if (numOne > 10 || numOne < -10) {
        printf("%d + ", numOne);
    }

    if (numTwo >= -10 && numTwo < 0) {
        printf("negative");    
    }
    if (numTwo == 0) {
        printf("zero");
    }
    if (numTwo == 1) {
        printf("one");
    }
    if (numTwo == 2) {
        printf("two");
    }
    if (numTwo == 3) {
        printf("three");
    }
    if (numTwo == 4) {
        printf("four");
    }
    if (numTwo == 5) {
        printf("five");
    }
    if (numTwo == 6) {
        printf("six");
    }
    if (numTwo == 7) {
        printf("seven");
    }
    if (numTwo == 8) {
        printf("eight");
    }
    if (numTwo == 9) {
        printf("nine");
    }
    if (numTwo == 10) {
        printf("ten");
    } else if (numTwo > 10 || numTwo < -10) {
        printf("%d = ", numTwo);
    }

    int total = numOne + numTwo;
    if (total >= -10 && total < 0) {
        printf(" = negative");    
    }
    if (total == 0) {
        printf(" = zero\n");
    }
    if (total == 1) {
        printf(" = one\n");
    }
    if (total == 2) {
        printf(" = two\n");
    }
    if (total == 3) {
        printf(" = three\n");
    }
    if (total == 4) {
        printf(" = four\n");
    }
    if (total == 5) {
        printf(" = five\n");
    }
    if (total == 6) {
        printf(" = six\n");
    }
    if (total == 7) {
        printf(" = seven\n");
    }
    if (total == 8) {
        printf(" = eight\n");
    }
    if (total == 9) {
        printf(" = nine\n");
    }
    if (total == 10) {
        printf(" = ten\n");
    } else if (total > 10 || total < -10) {
        printf(" = %d\n", total);
    }


    return 0;
}

Answer 1

这是因为您捕获了一个负数（插入“负数”），然后只检查数字1..10 以输出幅度。

最简单的解决方法可能是改变：

if (numOne == 1) {
    printf("one + ");
}

进入：

if (numOne == 1 || numOne == -1) {
    printf("one + ");
}

当然，其他的也一样。

---

或者，或者，您可以大大使用以下功能降低复杂性：

void outputNum(char *pre, int num, char *post) {
    static const char* lookup[] = { "zero", "one", "two", "three",
        "four", "five", "six", "seven", "eight", "nine", "ten" };
    if (num < -10 || num > 10) {
        printf("%s%d%s", pre, num, post);
    } else {
        if (num < 0)
            printf("%snegative %s%s", pre, lookup[-num], post);
        else
            printf("%s%s%s", pre, lookup[num], post);
    }
}

只需简单地调用它：

outputNum("Adding ", num1, "");
outputNum(" and ", num2, "");
outputNum(" gives you ", num1 + num2, "\n");

Answer 2

当变量为负数时，您可以更改变量的符号。喜欢：

if (numOne >= -10 && numOne < 0) {
    printf("negative");    
    numOne = -numOne;
}

那么剩下的代码只需要处理正值即可。

它要求您重新组织一些其他代码。比如这个：

int total = numOne + numTwo;

必须移动，以便在 scanf 之后完成

还可以考虑使用字符串数组而不是所有if 语句。 喜欢：

char numberToText[11][10] = {"zero", "one", "two", ... , "ten"};

那你就可以了

if (numOne < -10 || numOne  > 10)
{
    // special handling
}
else
{
    if (numOne < 0) numOne = -numOne;   // Change sign if negative
    printf("%s", numberToText[numOne]);
}

如果您不想更改numOne 的值，只需使用另一个变量即可：

if (numOne < -10 || numOne  > 10)
{
    // special handling
}
else
{
    int tmp = numOne;        // Copy to another variable and
    if (tmp < 0) tmp = -tmp; // make sure it's positive

    printf("%s", numberToText[tmp]);   // Use tmp as index
}