Mathematical expressions
The expr command is used to evaluate mathematical expressions. This command can address everything from simple addition and subtraction to advanced computations, such as sine and cosine. This eliminates the need to make system calls to perform advanced mathematical functions. The expr command evaluates the input and arguments, and returns an integer or floating-point value.
A Tcl expression consists of a combination of operators, operands, and parenthetical containers (parenthesis, braces, or brackets). There are no strict typing requirements, so any white space is stripped by the command automatically. Tcl supports non-numeric and string comparisons as well as Tcl-specific operators.
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