What's the difference between '...' and "..." in initialising a string? [duplicate]

Question

So, I can initialize a string in Fortran with both

CHARACTER(LEN=4)::string
string = "jklm"

and

CHARACTER(LEN=4)::string
string = 'jklm'

What's the difference?

Answer 1

At a glance of the fortan docs, it seems the same for the most part. Though if you plan to use a single quote within a string, use a double quote to enclose it.

// correct
"John's Stuff"

// wrong
'John's Stuff'

Alternatively:

// correct
'She said "Hey!"'
// wrong
"She said "Hey!""

http://www.fortran90.org/src/rosetta.html#strings-and-formatting

Edit: btw, same goes for most programming languages.