variable expression造句

variable names must not have the same form as a variable expression, such as
变量名不得使用与变量表达式相同的格式（例如
the foreach loop container uses an enumerator to perform the looping, whereas the for loop typically uses a variable expression
foreach循环容器使用枚举器执行循环，而for循环则通常使用变量表达式。
this paper presents a research on the representation method of assembly constraints in die & mold structure design, and discuss the solving approach of assembly constraints based on directed graph and variable expression
研究模具结构装配设计中装配约束的表示方法，并讨论基于有向图和变量表达式的装配约束的求解方法。
It's difficult to find variable expression in a sentence. 用variable expression造句挺难的