What is the result of concatenating two strings in most programming languages?

In most programming languages, concatenating (joining) two strings results in a new string that contains the characters of the first string followed by the characters of the second string.

In Go (Golang), it looks like this:

s1 := "Hello, "
s2 := "world!"
result := s1 + s2 // result will be "Hello, world!"

Thus, the + operator for strings concatenates their contents into a single string.