Question

用于将单词转换为大写或小写的函数将整个单词转换为大写或小写。我想要做的是将字符串中特定数量的字符转换为大写或小写。以单词串为例。如果用户只想将单词字符串中的字母S转换为大写，则输出应为：String。此外，此函数还会考虑他们想要转换的单词是否已经是大写或小写。

示例：用户输入单词STRING。想把这个词转换成STRing。输出：STRING

#include <iostream> 
#include <string>  
#include <cctype> 
using namespace std;

//Function Prototype
int CountVowels(string, int &);
void ShowMenu(string &, char &);
void convertword(string &);

int main()
{
//Variables
string word;
char choice = '0';
int vowels = 0;

do
{
//Call Functions
ShowMenu(word, choice);

switch(choice)
{
case '1':
    cout << CountVowels(word, vowels);
    cout << endl << endl;
    break;

case '2':
    convertword(word);
    cout << endl << endl;
    break;
}

}while(choice != '5');

return 0;
}

void ShowMenu(string& word, char& choice)
{
cout <<"\t\tMENU\t\t" << endl
     <<"===========================================" << endl;
cout <<"1. Find the number of Vowels in a word" << endl
     <<"2. Convert to uppercase or lowercase " << endl
     <<"3. Count the number of uppercase letters  " << endl
     <<"4. Count the number of lowercase letters" << endl
     <<"5. Quit"
     <<"\n===========================================" << endl;
//Get menu choice and get word from user.
cout << endl;
cout <<"Enter a choice: ";
cin >> choice;

while((!isdigit(choice)) || (choice > '5'))
{
    cerr << "\nOut of range or invalid input. ";
    cin >> choice;
}

cin.ignore();

cout << endl;

cout << "Enter a word: ";
getline(cin, word, '\n');


}

int CountVowels(string word, int& vowelCount)
{
vowelCount = 0;

int numLetters = word.length();  //get the number of letters in a word

for (int i = 0; i < numLetters; i++)
{
    char letter = word[i];  //get the ith letter in the word

    if (letter == 'a' || letter == 'e' ||
        letter == 'i' || letter == 'o' ||
        letter == 'u' || letter == 'y' )
    {
        vowelCount++;
    }


}

cout << "\nThe number of vowels in this word is : ";

return vowelCount;
}

void convertword(string &word)
{
bool same = false;
char response;

cout << "\nWould you like to convert this word to uppercase or lowercase. " << endl;
cout << "\nType U for uppercase and l for lowercase. ";
cin >> response;

while(response != 'U' && response != 'l')
{
    cerr  << "\nInvalid input. ";
    cin >> response;
}

for(unsigned int i=0; i<word.length(); i++)
{
    if((response == 'U' && word[i]==toupper(word[i])))
    {
        same = true;
    }
    else if(response == 'U')
    {
        word[i]=toupper(word[i]);
    }
    else if((response == 'l' && word[i]==tolower(word[i])))
    {
        same = true;
    }
    else if(response == 'l')
    {
        word[i]=tolower(word[i]);
    }
}

cout << endl;

if(same)
{
    cout << "\nBased on your response, this word has already been converted. ";
}
else
    cout << "\nyour newly converted or unconverted word is : " << word;
    cout << endl;
}

Answer 1

// Capitalizes the first letter and all others are lower case.
size_t n = the number of characters you want.
if( !word.empty() )
{
    if( n > word.size() )
        n = word.size();
    for( size_t i = 0; i < word.size(); ++i )
        word[i] = toupper( word[i] );
    for( size_t i = n; i < word.size(); ++i )
        word[i] = tolower( word[i] );
}

如何将特定数量的字符转换为大写或小写，并计算单词具有多少个大写和小写字母

1 个答案: