How Can I Use printf with a std::string in C ?

printf with std::string

printf is a C function, and std::string is a C class. That's why you're getting the error.

To fix this, you can use the c_str() method of std::string to get a C-style string that you can pass to printf. For example:

#include <iostream>
#include <string>
#include <stdio.h>

int main()
{
    using namespace std;

    string myString = "Press ENTER to quit program!";
    cout << "Come up and C++ me some time." << endl;
    printf("Follow this command: %s", myString.c_str());
    cin.get();

    return 0;
}

This will output:

Come up and C++ me some time.
Follow this command: Press ENTER to quit program!

If you don't want to use c_str(), you can also use the string stream class to format your output. For example:

#include <iostream>
#include <string>
#include <sstream>

int main()
{
    using namespace std;

    string myString = "Press ENTER to quit program!";
    cout << "Come up and C++ me some time." << endl;
    ostringstream oss;
    oss << "Follow this command: " << myString;
    printf("%s", oss.str().c_str());
    cin.get();

    return 0;
}

This will output the same as the previous example.

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