如何使用isalpha在C ++中的字符串中检查是否有特殊字符？

debugcn 发表于 Dev

time_in_real_time

在这里编码很新。我们正在使用isalpha函数，但在将其与字符串配合使用时遇到麻烦。我的程序将提示用户输入单词，然后该功能将检查单词是否包含任何特殊字符。基本上，我的代码只会说所有字符都是特殊字符，如果只有一对，则不会。我假设这与我的for循环有关，但是我无法弄清楚如何使其工作。我搜索了很多内容，但在C ++中找不到太多帮助。

这是我的功能。任何帮助表示赞赏。

//*****IsAlphaStr*****
//This function returns true if the cString passed contains all alphabetic characters.
//If the parameter does not contain all alpha characters, a value of false is returned.
bool IsAlphaStr(char wordcheck[25], bool alphabetic)
{
    int i = 0;
    int n = 0;

    for (int i = 0, n = strlen(wordcheck); i < n; i++)
    {   
        if (isalpha(wordcheck[i]) == 0)
            alphabetic = false;
        else
            alphabetic = true;
    }


    return alphabetic;
}

焦炭

如前所述，IsAlphaStr仅true当所有给定字符均为字母时才返回。这可以通过在条件break的false分支中添加a来实现if，这将停止for循环的进一步执行。

        if (isalpha(wordcheck[i]) == 0)
        {
            alphabetic = false;
            break;
        }

整个测试程序为：

#include <iostream>

//*****IsAlphaStr*****
//This function returns true if the cString passed contains all alphabetic characters.
//If the parameter does not contain all alpha characters, a value of false is returned.
bool IsAlphaStr(char wordcheck[25], bool alphabetic)
{
    int i = 0;
    int n = 0;

    for (int i = 0, n = strlen(wordcheck); i < n; i++)
    {   
        if (isalpha(wordcheck[i]) == 0)
        {
            alphabetic = false;
            break;
        }
        else
            alphabetic = true;
    }
    return alphabetic;
}

int main()
{
    char test1[25] = "abcdefghijklmnopqrstuvwx";
    char test2[25] = "0123456789ABCDEFGHIJKLMN";
    char test3[25] = "abcdefghijklmnopqres++-A";
    char test4[25] = "abcdefABCDEF";
    bool alphabetic = false;

    alphabetic = IsAlphaStr(test1, alphabetic);
    std::cout << "test1 = " << alphabetic << std::endl;
    alphabetic = IsAlphaStr(test2, alphabetic);
    std::cout << "test2 = " << alphabetic << std::endl;
    alphabetic = IsAlphaStr(test3, alphabetic);
    std::cout << "test3 = " << alphabetic << std::endl;
    alphabetic = IsAlphaStr(test4, alphabetic);
    std::cout << "test4 = " << alphabetic << std::endl;

    return 0;
}