Concatenation of two strings does not work [duplicate]

问题

This question already has an answer here:

Apparently not able to append a string to another (1 answer)

Closed 2 years ago.

I have the following code, but it doesn't work:

 CHARACTER*260 xx, yy, zz     
  xx = 'A'   
  yy = 'B'
  zz = xx // yy

When I debug my code in Visual Studio the

• variable xx contains 'A'
• variable yy contains 'B'
• variable zz contains 'A'

Why doesn't zz contain 'AB'?

回答1:

You defined xx to be 260 characters long. Assigning a shorter character literal will result in a padding with blanks. Thus, xx contains A and 259 blanks. yy contains B and 259 blanks. So the concatenated string would be 'A' + 259 blanks + 'B' + 259 blanks, in total 520 characters.

Since zz is only 260 characters long, the rest is cropped.

What you are trying to do is achieved by

zz = trim(xx) // trim(yy)

trim() removes trailing whitespace from strings.

来源：https://stackoverflow.com/questions/31134182/concatenation-of-two-strings-does-not-work