10 ASSIGNMENT STATEMENTS

There are four kinds of assignment statements:

1. Arithmetic
2. Logical
3. Statement label (ASSIGN)
4. Character

10.1 Arithmetic Assignment Statement

v = e

• where: v is the name of a variable or array element of type integer, real, double precision, or complex

• e is an arithmetic expression

Execution of an arithmetic assignment statement causes the evaluation of the expression e by the rules in Section 6, conversion of e to the type of v , and definition and assignment of v with the resulting value, as established by the rules in Table 4.

Arithmetic Conversion and Assignment of

               _________________ __________
              |                 |          |
              | Type of v       |  Value   |
              |_________________|__Assigned|
              |                 |          |
              | Integer         |  INT(e)  |
              |_________________|__________|
              |                 |          |
              |_Real____________|__REAL(e)_|
              |                 |          |
              | Double precision|  DBLE(e) |
              |_________________|__________|
              |                 |          |
              |_Complex_________|__CMPLX(e)|

The functions in the "Value Assigned" column of Table 4 are generic functions described in Table 5 ( 15.10).

10.2 Logical Assignment Statement

v = e

• where: v is the name of a logical variable or logical array element

• e is a logical expression

Execution of a logical assignment statement causes the evaluation of the logical expression e and the assignment and definition of v with the value of e . Note that e must have a value of either true or false.

10.3 Statement Label Assignment (ASSIGN) Statement

ASSIGN s TO i

• where: s is a statement label

• i is an integer variable name

Execution of an ASSIGN statement causes the statement label s to be assigned to the integer variable i . The statement label must be the label of a statement that appears in the same program unit as the ASSIGN statement. The statement label must be the label of an executable statement or a FORMAT statement.

Execution of a statement label assignment statement is the only way that a variable may be defined with a statement label value.

A variable must be defined with a statement label value when referenced in an assigned GO TO statement ( 11.3) or as a format identifier ( 12.4) in an input/output statement. While defined with a statement label value, the variable must not be referenced in any other way.

An integer variable defined with a statement label value may be redefined with the same or a different statement label value or an integer value.

10.4 Character Assignment Statement

v = e

• where: v is the name of a character variable, character array element, or character substring

• e is a character expression

Execution of a character assignment statement causes the evaluation of the expression e and the assignment and definition of v with the value of e . None of the character positions being defined in v may be referenced in e . v and e may have different lengths. If the length of v is greater than the length of e , the effect is as though e were extended to the right with blank characters until it is the same length as v and then assigned. If the length of v is less than the length of e , the effect is as though e were truncated from the right until it is the same length as v and then assigned.

Only as much of the value of e must be defined as is needed to define v . In the example:

1. CHARACTER A*2,B*4
2. A=B

the assignment A=B requires that the substring B(1:2) be defined. It does not require that the substring B(3:4) be defined.

If v is a substring, e is assigned only to the substring. The definition status of substrings not specified by v is unchanged.

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