将c++字符转换为数字大写和小写字符

#include <iostream>
#include <cctype>

int main() {
    char c = 'a';
    char upper = toupper(c) + '0';
    std::cout << "Character: " << c << std::endl;
    std::cout << "Uppercase digit: " << upper << std::endl;
    return 0;
}

Character: a
Uppercase digit: 6

#include <iostream>
#include <cctype>

int main() {
    char c = 'A';
    char lower = tolower(c) + '0';
    std::cout << "Character: " << c << std::endl;
    std::cout << "Lowercase digit: " << lower << std::endl;
    return 0;
}

Character: A
Lowercase digit: 9