Question

我希望打印出来＆＃34; getMostFreqLetter(s)的返回值为letter＆＃39; e＆＃39;，其频率为11。＆＃34;但是这个函数只能返回char类型的问题，我被困在这里，需要一些帮助

char getMostFreqLetter (string s){

    int maxNum = 0; // the max frequency of occurring of letters
    char maxChar = ' ';   // the max occurring of letters

    /* count the uppercase letters */
    for (char i = 65; i <= 90; i++){ // from A to z based on ascii table value
        int count = 0;  // count the frequency of occurring of letters which compare with maxMun

        for(int j = 0; j < s.length(); j++){
            if(s[j] == i){
                count ++;
            }

            /*  compare current frequency letters and existing most frequency letters */
            if(count > maxNum){ // display the first alphabet letter if there are multiple same frequency letters occurring
                maxNum = count;
                maxChar = i;
            }
        }
    }

    /* count the lowercase letters */
    for (char i = 97; i <= 122; i++){ // From a to z based on ascii table value
        int count = 0;  // Count the frequency of occurring of letters which compare with maxMun

        for(int j = 0; j < s.length(); j++){
            if(s[j] == i){
                count ++;
            }

            /* Compare current frequency letters and existing most frequency letters */
            if(count > maxNum){ // display the first alphabet letter if there are multiple same frequency letters occurring
                maxNum = count;
                maxChar = i;
            }
        }
    }

    //cout << "getMostFreqLetter(s) output: letter '" << maxChar <<"', whose frequency is " << maxNum  << "." << endl;

    return maxChar ; 
}

顺便说一句，有没有简单的方法将2个大写和小写的循环组合成一个循环？

Answer 1

对函数的最小更改是将其声明为：

std::pair<char,int> getMostFreqLetter (std::string s){

并将return语句设为：

return {maxChar, maxNum};

用法是：

const auto freq = getMostFreqLetter(s);
std::cout << "Most frequent letter is " << freq.first
            << " whose frequency is " << freq.second << std::endl;

最好使用适当类型的元素freq_t和letter来定义结构frequency。

为了加快速度，我会使用一个大小为CHAR_MAX的数组，并执行以下操作：

   for (const char ch: s)
       freq[(unsigned)ch]++;

强制转换是因为char可能会被签名，如果你有一个设置了最高位的字符，你就会对数组的前面进行索引。

然后你必须找到最高元素（而字符是索引）。

您可以将数组概念扩展为Unicode（这也可以避免强制转换）将std::map<unicode_char,int>用于unicode_char的合适选择。

如何在char的返回类型中打印出string和int的数据成员？

1 个答案: