C++のwcsspn関数を使った文字列処理の実践方法7選

#include <cwchar>  // ワイド文字列操作のためのヘッダファイルをインクルード

int main() {
    const wchar_t* str = L"example123";
    const wchar_t* set = L"abcdefghijklmnopqrstuvwxyz";

    // wcsspn関数を使用して、setに含まれる文字のみで構成される最長の部分文字列の長さを求める
    size_t length = wcsspn(str, set);

    // 結果の出力
    std::wcout << L"Length of initial segment containing only letters: " << length << std::endl;

    return 0;
}

#include <cwchar>
#include <iostream>

int main() {
    const wchar_t* input = L"12345abcde";
    const wchar_t* digits = L"0123456789";

    // wcsspnを使用して、数字のみで構成される文字列の長さを取得
    size_t skip = wcsspn(input, digits);

    // 最初の非数字文字の位置を出力
    std::wcout << L"First non-digit character appears at position: " << skip << std::endl;

    return 0;
}

#include <cwchar>
#include <iostream>

int main() {
    const wchar_t* username = L"JohnDoe123";
    const wchar_t* alphabet = L"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

    // wcsspnを使用して、アルファベットのみで構成される文字列の長さを取得
    size_t validLength = wcsspn(username, alphabet);

    // 入力検証
    if (wcslen(username) != validLength) {
        std::wcout << L"Invalid username. It must contain only alphabetic characters." << std::endl;
    } else {
        std::wcout << L"Username is valid." << std::endl;
    }

    return 0;
}

#include <cwchar>
#include <iostream>

int main() {
    const wchar_t* userInput = L"SELECT * FROM users WHERE user_id = 1;";
    const wchar_t* allowedChars = L"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 =*;";

    // wcsspnを使用して、許可された文字のみで構成される文字列の長さを取得
    size_t validInputLength = wcsspn(userInput, allowedChars);

    // 入力検証
    if (wcslen(userInput) != validInputLength) {
        std::wcout << L"Potential SQL injection detected!" << std::endl;
    } else {
        std::wcout << L"Input is safe." << std::endl;
    }

    return 0;
}

#include <cwchar>
#include <iostream>

int main() {
    const wchar_t* input = L"example";  // 正しくnull終端された文字列
    const wchar_t* set = L"abcdefghijklmnopqrstuvwxyz";

    // 文字列がnullで終わっているか確認
    if (input[wcslen(input)] != L'\0') {
        std::wcout << L"String is not null-terminated!" << std::endl;
        return -1;
    }

    size_t result = wcsspn(input, set);
    std::wcout << L"Length of initial segment containing only letters: " << result << std::endl;

    return 0;
}

#include <cwchar>
#include <iostream>
#include <vector>
#include <string>

int main() {
    const wchar_t* input = L"verylonginputstringwithmanycharacters";
    const wchar_t* set = L"abcdefghijklmnopqrstuvwxyz";
    std::vector<std::wstring> segments = {L"verylong", L"inputstring", L"withmany", L"characters"};

    size_t total = 0;
    for (const auto& segment : segments) {
        size_t length = wcsspn(segment.c_str(), set);
        total += length;
        if (length != segment.size()) break;  // 不一致が見つかったらループを抜ける
    }

    std::wcout << L"Total length of segments matching the character set: " << total << std::endl;

    return 0;
}

#include <cwchar>
#include <iostream>

int main() {
    const wchar_t* inputData = L"data123<script>";
    const wchar_t* allowedChars = L"abcdefghijklmnopqrstuvwxyz1234567890";

    // wcsspnを使用して、許可された文字のみで構成される文字列の長さを取得
    size_t validLength = wcsspn(inputData, allowedChars);

    // 入力が不正な文字を含むかチェック
    if (wcslen(inputData) != validLength) {
        std::wcout << L"Input contains invalid characters." << std::endl;
    } else {
        std::wcout << L"Input is clean and safe." << std::endl;
    }

    return 0;
}

#include <cwchar>
#include <iostream>

int main() {
    const wchar_t* username = L"user1234$#%";
    const wchar_t* validChars = L"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

    size_t validLength = wcsspn(username, validChars);

    // ユーザー名が無効な文字を含んでいる場合はエラーメッセージを出力
    if (wcslen(username) != validLength) {
        std::wcout << L"Username contains invalid characters. Only alphabets and numbers are allowed." << std::endl;
    } else {
        std::wcout << L"Username is valid." << std::endl;
    }

    return 0;
}

#include <cwchar>
#include <iostream>

int main() {
    const wchar_t* input = L"こんにちは123";
    const wchar_t* allowedChars = L"あいうえおかきくけこさしすせそたちつてとなにぬねのはひふへほまみむめもやゆよらりるれろわをん0123456789";

    size_t length = wcsspn(input, allowedChars);

    if (wcslen(input) != length) {
        std::wcout << L"Input contains unauthorized characters." << std::endl;
    } else {
        std::wcout << L"All characters are valid." << std::endl;
    }

    return 0;
}

#include <cwchar>
#include <iostream>
#include <vector>
#include <string>

int main() {
    const wchar_t* userInput = L"DataWithSymbols#@$";
    std::vector<std::wstring> filters = {L"abcdefghijklmnopqrstuvwxyz", L"ABCDEFGHIJKLMNOPQRSTUVWXYZ", L"0123456789"};

    size_t totalValidLength = 0;
    for (const auto& filter : filters) {
        totalValidLength += wcsspn(userInput, filter.c_str());
    }

    if (wcslen(userInput) != totalValidLength) {
        std::wcout << L"User input contains invalid characters." << std::endl;
    } else {
        std::wcout << L"User input is completely valid." << std::endl;
    }

    return 0;
}