The code doesn't work because you're using wrong syntax for \ifthenelse . Please check the syntax: ... <看更多>

package types;. /**. * IfThenElse expression form. */. public class IfThenElse extends Expr {. public Expr ifExpr, thenExpr, elseExpr;. ... <看更多>

IfThenElse, Lda. · 公共主页 · 商业服务 · loja.ite.pt · 评分· 5.0（9 条点评）. ... <看更多>

IfThenElse ¶. A member of the ControlConstruct substitution group. Describes an if-then-else decision type of control construct. IF the stated condition is ... ... <看更多>

IF-THEN-ELSE statement in qbasic | IF--THEN-ELSE | computeraddiction ... IF ELSE Function in EXCEL for Beginners | IF THEN ELSE and IF THEN ELSE IF THEN ... ... <看更多>

My little example is as follows: \documentclass{article} \usepackage{xifthen} \newcommand{{\xx}}[2][]{ \ifthenelse{\isempty{#1}}{ ... ... <看更多>