Question

How to extract capital letters from a string in C++

Answer 1

#include <iostream>

#define BUFFER_SIZE 64 
 
void extractCapitalLetters(std::string str, char *buf) {
    size_t idx = 0;
     
    if (!buf || str == "") { 
        std::cout << "error: invalid parameter.\n";
        return;
    }
 
    for (int i = 0; i <  str.length(); i++) {
        if (str[i] >= 'A' && str[i] <= 'Z') {
            buf[idx++] = str[i]; 
        }
    }
}
 
int main ()
{    
    std::string str = "C++ is a High-leveL General-purpose pRogramMing LanguagE";
    char capital_letters[BUFFER_SIZE] = "";
 
    extractCapitalLetters(str, capital_letters);
 
    std::cout << capital_letters;
}
 
   
   
    
/*
run:
      
CHLGRMLE
    
*/

 

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Answer 2

#include <iostream>

#define BUFFER_SIZE 64 
 
std::string extractCapitalLetters(std::string str) {
    if (str == "") { 
        std::cout << "error: invalid parameter.\n";
        return "";
    }
    
    std::string capital_letters = "";
 
    for (int i = 0; i <  str.length(); i++) {
        if (str[i] >= 'A' && str[i] <= 'Z') {
            capital_letters += str[i]; 
        }
    }
    
    return capital_letters;
}
 
int main ()
{    
    std::string str = "C++ is a High-leveL General-purpose pRogramMing LanguagE";

    std::string capital_letters = extractCapitalLetters(str);
 
    std::cout << capital_letters;
}
 
   
   
    
/*
run:
      
CHLGRMLE
    
*/

 

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