Character Expressions

A character expression is an expression whose operands have the character type. It evaluates to a single value of type character, with a size of one or more characters. The only character operator is the concatenation operator, //.

Expression	Meaning
a // z	Concatenate a with z.

The result of concatenating two strings is a third string that contains the characters of the left operand followed immediately by the characters of the right operand. The value of a concatenation operation a//z is a character string whose value is the value of a concatenated on the right with the value of z, and whose length is the sum of the lengths of a and z.

The operands can be any of the following kinds of data items:

• Character constant

• Character variable

• Character array element

• Character function

• Substring

• Structured record field (if it evaluates to a scalar character data item)

Examples: Character expressions, assuming C, S, and R.C are characters:

---

	'wxy'
	'AB' // 'wxy'
	C 
	C // S 
	C(4:7) 
	R.C 

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Note the following (nonstandard) exceptions:@

• Control characters--One way to enter control characters is to hold down the Control key and press another key. Most control characters can be entered this way, but not Control-A, Control-B, Control-C, or Control-J.

  Example: A valid way to enter a Control-C:

  ---

  	CHARACTER etx
  	etx = CHAR(3)

  ---

• Multiple byte characters--Multiple byte characters, such as Kanji, are allowed in comments and strings.

Character String Assignment

The form of the character string assignment is:

v = e
e	Expression giving the value to be assigned
v	Variable, array element, substring, or character record field

The meaning of character assignment is to copy characters from the right to the left side.

Execution of a character assignment statement causes evaluation of the character expression and assignment of the resulting value to v.

• If e is longer than v, characters on the right are truncated.

• If e is shorter than v, blank characters are padded on the right.

Example: The following program below displays joinedDD:

---

	CHARACTER A*4, B*2, C*8 
	A = 'join'
	B = 'ed'
	C = A // B 
	PRINT *, C 
	END 

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Also, this program displays the equal string:

---

	IF ( ('ab' // 'cd') .EQ. 'abcd' ) PRINT *, 'equal'
	END

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Example: Character assignment:

---

	CHARACTER BELL*1, C2*2, C3*3, C5*5, C6*6 
	REAL Z
	C2 = 'z' 
	C3 = 'uvwxyz' 
	C5 = 'vwxyz' 
	C5(1:2) = 'AB' 
	C6 = C5 // C2 
	I = 'abcd' 
	Z = 'wxyz'
	BELL = CHAR(7)    Control Character (^G)

---

The results are:

Variable	Receiving Value	Comment
C2	'zD'	A trailing blank
C3	'uvw'
C5	'ABxyz'
C6	'ABxyzz'	The final 'z' comes from C2
I	'abcd'
Z	'wxyz'
BELL	07 hex	Control-G, a bell

Example 4: A Hollerith assignment: @

---

	CHARACTER S*4 
	INTEGER I2*2, I4*4 
	REAL R 
	S = 4Hwxyz 
	I2 = 2Hyz 
	I4 = 4Hwxyz 
	R = 4Hwxyz 

---

Rules of Assignment

Here are the rules for character assignments:

• If the left side is longer than the right, it is padded with trailing blanks.

• If the left side is shorter than the right, trailing characters are discarded.

• The left and right sides of a character substring assignment cannot overlap. See the "Substrings" .