drygdryg/calc
1
0
Fork 0
mirror of https://github.com/lcn2/calc.git synced 2025-08-16 01:03:29 +03:00
Code Issues Packages Projects Releases Wiki Activity

Release calc version 2.10.3t5.45

Browse Source
This commit is contained in:
Landon Curt Noll
1997-10-04 20:06:29 -07:00
parent 4618313a82
commit 6e10e97592
300 changed files with 38279 additions and 8584 deletions
Download Patch File Download Diff File Expand all files Collapse all files

55
help/operator
View File

@@ -1,14 +1,16 @@
operators
The operators are similar to C, but there are some differences
in the associativity and precedence rules for some operators.
In addition, there several operators not in C, and some C operators
are missing. Below is a list giving the operators arranged in
order of precedence, from the least tightly binding to the most
tightly binding.
The operators are similar to C, but there are some differences in
the associativity and precedence rules for some operators. In
addition, there are several operators not in C, and some C
operators are missing. A more detailed discussion of situations
that may be unexpected for the C programmer may be found in
the 'unexpected' help file.
Except where otherwise indicated, operators at the same level of
precedence associate from left to right.
Below is a list giving the operators arranged in order of
precedence, from the least tightly binding to the most tightly
binding. Except where otherwise indicated, operators at the same
level of precedence associate from left to right.
Unlike C, calc has a definite order for evaluation of terms (addends
in a sum, factors in a product, arguments for a function or a
@@ -55,13 +57,24 @@ operators
, Comma operator.
a, b returns the value of b.
For situations in which a comma is used for another purpose
(function arguments, array indexing, and the print statement),
parenthesis must be used around the comma operator.
parenthesis must be used around the comma operator expression.
E.g., if A is a matrix, A[(a, b), c] evaluates a, b, and c, and
returns the value of A[b, c].
= += -= *= /= %= //= &= |= <<= >>= ^= **=
Assignments. As in C, these associate from right to left.
+= -= *= /= %= //= &= |= <<= >>= ^= **=
Operator-with-assignments.
These associate from left to right, e.g. a += b *= c has the
effect of a = (a + b) * c, where only a is required to be an
lvalue. For the effect of b *= c; a += b; when both a and b
are lvalues, use a += (b *= c).
= Assignment.
As in C, this, when repeated, this associates from right to left,
e.g. a = b = c has the effect of a = (b = c). Here both a and b
are to be lvalues.
? : Conditional value.
a ? b : c returns b if a tests as true (i.e. nonzero if
@@ -90,7 +103,8 @@ operators
Relations.
+ -
Binary plus and minus.
Binary plus and minus and unary plus and minus when applied to
a first or only term.
* / // %
Multiply, divide, and modulo.
@@ -129,13 +143,19 @@ operators
e.g. a << b ^ c = a << (b ^ c).
+ - !
Unary operators.
The '!' is the logical NOT operator: !a returns 0 if
a is nonzero, and 1 if a is zero, i.e. it is
Plus (+) and minus (-) have their usual meanings as unary
prefix operators at this level of precedence when applied to
other than a first or only term.
As a prefix operator, '!' is the logical NOT: !a returns 0 if
a tests as nonzero, and 1 if a tests as zero, i.e. it is
equivalent to a ? 0 : 1. Be careful about
using this as the first character of a top level command,
since it is also used for executing shell commands.
As a postfix operator ! gives the factorial function, i.e.
a! = fact(a).
++ --
Pre or post incrementing or decrementing.
These are applicable only to variables.
@@ -183,3 +203,8 @@ operators
The shift amount must be an integer. The value being
shifted must be an integer or a complex number with
integral real and imaginary parts.
See the 'unexpected' help file for a list of unexpected
surprises in calc syntax/usage. Persons familiar with C should
read the 'unexpected' help file to avoid confusion.