We can use the **`format()`** function in C++20 to format strings. To use the `format()` function, we must include the following library:
```C
#include <format>
```
# Declaration
The `format()` function can be declared as follows:
```C
template< class... T >
std::string format( const std::locale& local, format, const T &... param );
```
OR
```C
template< class... T >
std::wstring format( const std::locale& local, format, const T &... param );
```
* `param`: The strings being formatted.
* `format`: The format string to format `param`. This is a parameter of unspecified type.
* `local`: This is an optional parameter used for locale-specific formatting.

> Note: We use `{}` as a placeholder of `param` in `format`. 

# Return type
The `format()` function returns a string that is the arguments `param` formatted as `format`.



# Code
Consider the code snippet below, which demonstrates the use of the `format()` function:

#include <iostream>
#include <format>
 
int main() {
    std::cout << std::format("Hello {}!! \n", "world");
    std::cout << std::format("My name is {0}. I love {1}. \n", "Ali", "Educative");
}

## Output
```C
Hello world!!
My name is Ali. I love Educative.

```

## Explanation
* *line 5*: `{}` is used as the placeholder of the string "world." At runtime, `{}` is replaced with the string "world."
* *line 6*: `{0}` is replaced with the first string to be formatted, "Ali." Similarly, `{1}` is replaced with the second string to be formatted, "Educative." 


How to format a string in C++20

Declaration

Return type

Code

Output

Explanation