c++ check if string contains non alphanumeric

Sure! Here is an example of how you can check if a string contains non-alphanumeric characters in C++:

#include <iostream>
#include <string>
#include <cctype>

bool containsNonAlphanumeric(const std::string& str) {
    for (char c : str) {
        if (!std::isalnum(c)) {
            return true;
        }
    }
    return false;
}

int main() {
    std::string input;
    std::cout << "Enter a string: ";
    std::cin >> input;

    if (containsNonAlphanumeric(input)) {
        std::cout << "The string contains non-alphanumeric characters." << std::endl;
    } else {
        std::cout << "The string does not contain non-alphanumeric characters." << std::endl;
    }

    return 0;
}

Explanation of the code:

• The containsNonAlphanumeric function takes a std::string as input and returns a boolean value indicating whether the string contains non-alphanumeric characters.
• The function uses a for loop to iterate through each character in the string.
• Inside the loop, the std::isalnum function is used to check if the character is alphanumeric. If it is not alphanumeric, the function returns true immediately.
• If the loop completes without finding any non-alphanumeric characters, the function returns false.
• In the main function, the user is prompted to enter a string.
• The containsNonAlphanumeric function is called with the input string, and the result is used to determine whether the string contains non-alphanumeric characters.
• Finally, a message is printed to the console indicating whether the string contains non-alphanumeric characters or not.

I hope this helps! Let me know if you have any further questions.