#include "nsString.h" int main() { nsAString str = NS_LITERAL_STRING("The value is: "); int num = 42; str.AppendInt(num); printf("%s\n", NS_ConvertUTF16toUTF8(str).get()); return 0; }In this example, we first initialize an nsAString object with some text. We then declare an integer variable `num` and set its value to `42`. We then call `AppendInt` on the `str` object, which appends the string representation of `num` ("42") to the end of the string. We then convert the string to UTF-8 and print it to the console. This example demonstrates how to use nsAString AppendInt to append an integer value to a string using the Mozilla XPCOM library.