| .CALL (BASIC Procedures) Statement Details. |
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| CALL (BASIC Procedures) Statement Details |
|
| Syntax |
| CALL name[(argumentlist)] |
| |
| Argument Description |
| name The name, limited to 40 characters, of the BASIC SUB |
| being called. The name must appear in a SUB statement |
| if the SUB is in the same module. |
| |
| argumentlist The variables or constants passed to the subprogram. |
| Arguments in the list are separated by commas. |
| Arguments passed by reference can be changed by the |
| subprogram. |
| |
| If the argumentlist includes an array argument, the array is specified |
| by the array name followed by empty parentheses: |
| |
| DIM IntArray(1 TO 20) |
| . |
| . |
| . |
| CALL ShellSort(IntArray()) |
| |
| When you use the CALL statement, the CALL keyword is optional. |
| However, if you omit the CALL keyword, you must declare the procedure |
| in a DECLARE statement. Notice also that when you omit the CALL |
| keyword, you also omit the parentheses around the argument list. |
| |
| Arguments are passed by reference: the subprogram is given the address |
| of the argument. This allows subprograms to change the argument values. |
| BASIC can also pass arguments by value. The following statement calls |
| a subprogram and passes a single argument by value: |
| |
| CALL SolvePuzzle((StartValue)) |
| |
| Because StartValue is in parentheses, BASIC evaluates it as an |
| expression. The result is stored in a temporary location, and the |
| address of the temporary location is passed to the SUB. Any change |
| made by the subprogram SolvePuzzle is made only to the temporary |
| location and not to the variable. |
