c - C程序中用于检查字符大小写的 bool 错误

Question

你好，我正在编写一个 C 程序，我有一个名为 bool is_proper_case(char str[]) 的辅助函数，如果大写字母仅出现在 str 的开头或紧跟在句点之后，该函数将返回 true。此外，只有大写字母或 NULL 终止符可以跟在句点之后。例子是:

assert(is_proper_case("Hello world.") == true);
assert(is_proper_case("hello world.") == true);
assert(is_proper_case("i like C language.very much.") == false);
assert(is_proper_case("This sentence is not.correct.") == false);

编辑代码:

bool is_proper_case(char str[]) {

int len = 0;

for (int j=0 ;str[j]!= 0 ; j++)
{

 len++;
}

int output = 0;

for (int i=0 ; i<=len-1 ; i++)

{
   if (str[i]=='.'&& (str[i+1]<='z' && str[i+1]>='a'))
   {
     output = 0;
   }

   else if ('A'<=str[i]<='Z')
   {
    output = 1;
   }

   else output = 0 ;
     }
       printf ("%d", output);
      return output;
      }

我的问题是:我无法断言上述陈述，我断言失败了。(有一些逻辑错误)

我不知道我在这段代码中遗漏了什么请注意，我是 C 编程的初学者所以请耐心等待。

提前致谢

Answer 1

下面的代码应该可以完成你想要的。我确实写了一堆注释来帮助您理解代码中发生的事情。希望你能明白。您可能想要支持一些额外的东西:

1. 句点后的单个空白。像这样。
2. 连续三个时期。它继续......
3. 全上“词”，例如 USA。

---

#include <assert.h> // for assert()
#include <stdbool.h> // bool support in C99 or higher.
#include <stdlib.h> // for EXIT_SUCCESS
#include <string.h> // for strlen()

bool has_proper_case(const char *str) {
    // Start by assuming the string has proper case. Conforming.
    bool result = true;
    // How long is the string?
    const size_t len = strlen(str);

    // State variables
    bool is_upper = false;
    bool is_period = false;
    bool is_after_period = false;

    // Iterate over the entire string.
    for (size_t i=0; i < len; i++) {
        // This will only be true if the previous character was a period.
        is_after_period = is_period;
        // This will only be true if the current character is a period.
        is_period = str[i] == '.';
        // This will only be true if the current character is uppercase.
        is_upper = str[i] >= 'A' && str[i] <= 'Z';

        if (i > 0) // Are we past the beginning of the string?
        {
            // Uppercase is mandated after a period.
            if (is_after_period && !is_upper) {
                result = false; // Set the result to false. Non-conforming.
                break; // Break out of the loop.
            }
            // Uppercase is not tolerated anywhere besides after a period.
            if (is_upper && !is_after_period) {
                result = false; // Set the result to false. Non-conforming.
                break; // Break out of the loop.
            }
        } else { // Are we at the beginning of the string?
            // Uncomment if uppercase is mandated at the beginning of the string.
            // if (!is_upper) {
            //  result = false;
            //  break;
            // }
        }
    }

    return result;
}

int main()
{
    assert(has_proper_case("Hello world.") == true);
    assert(has_proper_case("hello world.") == true);
    assert(has_proper_case("Uppercase is mandated after a period.Test") == true);
    assert(has_proper_case("Uppercase is mandated after a period.test") == false);
    assert(has_proper_case("Uppercase is mandated after a period. test") == false);
    assert(has_proper_case("Uppercase is NOT tolerated anywhere besides after a period.Test") == false);
    return EXIT_SUCCESS;
}