Question

How to convert a string to uppercase in C++

Answer 1

#include <iostream>
#include <algorithm>

int main() {
    std::string s = "c++ programming";

    std::transform(s.begin(), s.end(), s.begin(), ::toupper);

    std::cout << s;
}



/*
run:

C++ PROGRAMMING

*/

 

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Answer 2

#include <iostream>

int main() {
    std::string s = "c++ programming";

    for (auto & ch: s) ch = toupper(ch);

    std::cout << s;
}



/*
run:

c++ programming

*/

 

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Answer 3

#include <iostream>
#include <algorithm> 
   
std::string string_toupper(std::string s) {
    for_each(s.begin(), s.end(), [](char & ch) {
        ch = toupper(ch);
    });
       
    return s;
}
   
int main() {
    std::string s = "cpp programming"; 
       
    s = string_toupper(s);
       
    std::cout << s;
}

   
   
/*
run:
   
CPP PROGRAMMING
   
*/

 

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