やったこと
tolower, toupper を使ってみます。
確認環境
$ g++ --version
g++ (Homebrew GCC 9.2.0) 9.2.0
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
調査
test.cpp
#include <bits/stdc++.h>
using namespace std;
int main() {
string s1 = "abcdef";
string s2 = "ABCDEF";
s1[4] = toupper(s1[4]);
s2[2] = tolower(s2[1]);
cout << s1 << endl;
cout << s2 << endl;
}
出力結果
abcdEf
ABbDEF