相当于 sprintf 的 C + + ？

std::ostringstream

Example:

#include <iostream>
#include <sstream> // for ostringstream
#include <string>


int main()
{
std::string name = "nemo";
int age = 1000;
std::ostringstream out;
out << "name: " << name << ", age: " << age;
std::cout << out.str() << '\n';
return 0;
}

Output:

name: nemo, age: 1000

Use a stringstream to achieve the same effect. Also, you can include <cstdio> and still use snprintf.

sprintf works just fine in C++.

Update, August 2019:

It looks like C++20 will have std::format. The reference implementation is {fmt}. If you are looking for a printf() alternative now, this will become the new "standard" approach and is worth considering.

Original:

Use Boost.Format. It has printf-like syntax, type safety, std::string results, and lots of other nifty stuff. You won't go back.

Here's a nice function for a c++ sprintf. Streams can get ugly if you use them too heavily.

std::string string_format(std::string fmt, ...) {
int size=100;
std::string str;
va_list ap;


while (1) {
str.resize(size);
va_start(ap, fmt);
int n = vsnprintf(&str[0], size, fmt.c_str(), ap);
va_end(ap);
   

if (n > -1 && n < size) {
str.resize(n); // Make sure there are no trailing zero char
return str;
}
if (n > -1)
size = n + 1;
else
size *= 2;
}
}

In C++11 and later, std::string is guaranteed to use contiguous storage that ends with '\0', so it is legal to cast it to char * using &str[0].

You can use iomanip header file to format the output stream. Check this!

Depending on what exactly you plan on sprintf()ing, std::to_string() might be useful and more idiomatic than other options:

void say(const std::string& message) {
// ...
}


int main() {
say(std::to_string(5));
say("Which is to say " + std::to_string(5) + " words");
}

The main advantage of std::to_string(), IMHO, is that it can be extended easily to support additional types that sprintf() can't even dream of stringifying - kind of like Java's Object.toString() method.