函数由一句或多句代码组成，可以实现某个特定的功能。使用函数可以使代码更加易读、易懂，加快编程速度及减少重复代码。过程与函数类似，过程与函数最重要的区别在于，过程没有返回值，而函数能有返回值。 　　在Delphi 7.0中，已为我们定义好了非常多的函数，大致分类有6种：数据类型转换函数、字符串、数组操作函数、文件、磁盘操作函数、内存、指针操作函数、数学运算函数、日期函数。-function sentence by one or more code components, can achieve a particular function. You can use your code more readable, understandable, accelerate programming speed and reducing duplication of code. Similar processes and functions, processes and functions most important difference is that the process did not go to the value and the function can return value. In Delphi 7.0, we have a very good definition of function, broadly categorized into six types : data conversion functions, string and array manipulation functions, documents, disk manipulation functions, memory, pointer manipulation functions, arithmetic function, the date function.