Question

您好我正在编写一个C程序，并且我有一个名为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，则返回true。而且，只有大写字母或NULL终止符可以跟随一段时间。例如：

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);

已编辑的代码：

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，我没有断言。（有一些逻辑错误）

我不知道我在这个片段中缺少什么，请知道，我是C编程的初学者，请耐心等待。

提前致谢

Answer 1

一次，if (str[i]=='.'&& (str[i]<='z' && str[i+1]>='a'))对于ASCII始终为false，因为点不在z和a之间。

此外，只有当str [i]是大写字母时才会到达此行，因此它似乎根本不在正确的位置。

Answer 2

以下代码应该可以实现您的目标。我写了一堆评论来帮助你理解代码中发生了什么。希望你能得到这个想法。你可能想要支持一些额外的东西：

一段时间后的单一空白区域。像这样。
连续三个时期。它继续......
所有上层“单词”，例如美国。

#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;
}

C程序中的Bool错误检查字符大小写

2 个答案: