Mercurial > octave-nkf
comparison doc/interpreter/stmt.txi @ 9209:923c7cb7f13f
Simplify TeXinfo files by eliminating redundant @iftex followed by @tex construction.
spellchecked all .txi and .texi files.
| author | Rik <rdrider0-list@yahoo.com> |
|---|---|
| date | Sun, 17 May 2009 12:18:06 -0700 |
| parents | fca0dc2fb042 |
| children | 322f43e0e170 |
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| 9208:cb163402bf79 | 9209:923c7cb7f13f |
|---|---|
| 218 It is very common to take different actions depending on the value of | 218 It is very common to take different actions depending on the value of |
| 219 one variable. This is possible using the @code{if} statement in the | 219 one variable. This is possible using the @code{if} statement in the |
| 220 following way | 220 following way |
| 221 | 221 |
| 222 @example | 222 @example |
| 223 @group | |
| 223 if (X == 1) | 224 if (X == 1) |
| 224 do_something (); | 225 do_something (); |
| 225 elseif (X == 2) | 226 elseif (X == 2) |
| 226 do_something_else (); | 227 do_something_else (); |
| 227 else | 228 else |
| 228 do_something_completely_different (); | 229 do_something_completely_different (); |
| 229 endif | 230 endif |
| 231 @end group | |
| 230 @end example | 232 @end example |
| 231 | 233 |
| 232 @noindent | 234 @noindent |
| 233 This kind of code can however be very cumbersome to both write and | 235 This kind of code can however be very cumbersome to both write and |
| 234 maintain. To overcome this problem Octave supports the @code{switch} | 236 maintain. To overcome this problem Octave supports the @code{switch} |
| 235 statement. Using this statement, the above example becomes | 237 statement. Using this statement, the above example becomes |
| 236 | 238 |
| 237 @example | 239 @example |
| 240 @group | |
| 238 switch (X) | 241 switch (X) |
| 239 case 1 | 242 case 1 |
| 240 do_something (); | 243 do_something (); |
| 241 case 2 | 244 case 2 |
| 242 do_something_else (); | 245 do_something_else (); |
| 243 otherwise | 246 otherwise |
| 244 do_something_completely_different (); | 247 do_something_completely_different (); |
| 245 endswitch | 248 endswitch |
| 249 @end group | |
| 246 @end example | 250 @end example |
| 247 | 251 |
| 248 @noindent | 252 @noindent |
| 249 This code makes the repetitive structure of the problem more explicit, | 253 This code makes the repetitive structure of the problem more explicit, |
| 250 making the code easier to read, and hence maintain. Also, if the | 254 making the code easier to read, and hence maintain. Also, if the |
| 281 is executed if @emph{any} of the elements of the cell array match | 285 is executed if @emph{any} of the elements of the cell array match |
| 282 @var{expression}. As an example, the following program will print | 286 @var{expression}. As an example, the following program will print |
| 283 @samp{Variable is either 6 or 7}. | 287 @samp{Variable is either 6 or 7}. |
| 284 | 288 |
| 285 @example | 289 @example |
| 290 @group | |
| 286 A = 7; | 291 A = 7; |
| 287 switch A | 292 switch A |
| 288 case @{ 6, 7 @} | 293 case @{ 6, 7 @} |
| 289 printf ("variable is either 6 or 7\n"); | 294 printf ("variable is either 6 or 7\n"); |
| 290 otherwise | 295 otherwise |
| 291 printf ("variable is neither 6 nor 7\n"); | 296 printf ("variable is neither 6 nor 7\n"); |
| 292 endswitch | 297 endswitch |
| 298 @end group | |
| 293 @end example | 299 @end example |
| 294 | 300 |
| 295 As with all other specific @code{end} keywords, @code{endswitch} may be | 301 As with all other specific @code{end} keywords, @code{endswitch} may be |
| 296 replaced by @code{end}, but you can get better diagnostics if you use | 302 replaced by @code{end}, but you can get better diagnostics if you use |
| 297 the specific forms. | 303 the specific forms. |
| 311 string will be made instead of evaluating if the strings are equal. | 317 string will be made instead of evaluating if the strings are equal. |
| 312 This special-case is handled by the @code{switch} statement, and it | 318 This special-case is handled by the @code{switch} statement, and it |
| 313 is possible to write programs that look like this | 319 is possible to write programs that look like this |
| 314 | 320 |
| 315 @example | 321 @example |
| 322 @group | |
| 316 switch (X) | 323 switch (X) |
| 317 case "a string" | 324 case "a string" |
| 318 do_something | 325 do_something |
| 319 @dots{} | 326 @dots{} |
| 320 endswitch | 327 endswitch |
| 328 @end group | |
| 321 @end example | 329 @end example |
| 322 | 330 |
| 323 @menu | 331 @menu |
| 324 * Notes for the C programmer:: | 332 * Notes for the C programmer:: |
| 325 @end menu | 333 @end menu |
| 579 @end group | 587 @end group |
| 580 @end example | 588 @end example |
| 581 | 589 |
| 582 @noindent | 590 @noindent |
| 583 In the above case, the multidimensional matrix @var{c} is reshaped to a | 591 In the above case, the multidimensional matrix @var{c} is reshaped to a |
| 584 two dimensional matrix as @code{reshape (c, rows(c), | 592 two-dimensional matrix as @code{reshape (c, rows(c), |
| 585 prod(size(c)(2:end)))} and then the same behavior as a loop over a two | 593 prod(size(c)(2:end)))} and then the same behavior as a loop over a two |
| 586 dimensional matrix is produced. | 594 dimensional matrix is produced. |
| 587 | 595 |
| 588 Although it is possible to rewrite all @code{for} loops as @code{while} | 596 Although it is possible to rewrite all @code{for} loops as @code{while} |
| 589 loops, the Octave language has both statements because often a | 597 loops, the Octave language has both statements because often a |