Dim statement

The DIM statement in Program QENTROPY sets aside 100 memory locations for the experimental data points. It is necessary for any data set having more than 12 data pairs. What is the entropy of Pb at 100 and 200 K Make a rough sketch of the curve of C, vs. T for lead. Sketch the curve of Cp/T vs. T for lead. 

Strings can be stored either as variable-length strings (the default data type) or as fixed-length strings. To declare a string variable as fixed-length, use the statement in a Dim statement (more about the Dim statement in Chapter 15)... 

You can force a particular variable or argument to take a specified data type. For variables, use the Dim statement, e.g.. 

The Dim statement is used to declare the size of an array. Unless specified otherwise, VBA arrays begin with an index of 0. The statement... 

You can specify the lower bound of an array in the Dim statement. For example. 

It s considered good programming practice to put the Dim statements at the beginning of the procedure. 

Since multidimensional arrays such as the one above can use up significant amounts of memory, it s important to define the data type of the variable. The complete syntax of the Dim statement is... 

Several variables can be dimensioned in a single Dim statement, but there must be a separate As Type for each variable. 

If a variable in a VBA Sub procedure is set equal to a range of cells in a worksheet, that variable becomes an array. No Dim statement is necessary. Thus the following expression in Figure 15-2 creates a VBA array called TestArray ... 

If a range argument is passed in a function macro, the range automatically becomes an array in the VBA procedure. No Dim statement is necessary. Thus the expression... 

Shows one way to return an array of values Create an actual array by using the Dim statement. 

As shown in Figure 4.B.2, the Aspen Plus simulation file is opened first. In VBA, Dim statement is used for declaration of variables, whereas Set statement is used for creating new objects. Then, values of feed flow rate, feed heater outlet temperature, reflux ratio for column 1 and feed stage for column 2 and number of stages for column 3 are transferred from cells C3 to C7 in Excel worksheet named DV to Aspen Plus , to Aspen Plus... 

It was not necessary to include a DIM statement to establish that X stood for a vector, as in ... 

Such a DIM statement could be included, to be sure, but if one were satisfied to work with elements X(l) through X(10), the DIM statement would not be required. While supplying sensible default values is stiU a cornerstone of BASIC, default dimensioning of arrays has given way to multi-character function names. 

Every time you add any tests with new variables, you need to remember to include the variables in the appropriate dimension Dim statements (see Figure 4-B1). 

The first two items are compiler options. The Option Explicit makes it imperative that the data type of all variables be declared (using a Dim statement). The Option Base 1 makes any arrays (there are none in this first program) start with a subscript of 1. 

An Array is the eqnivalent of a subscripted variable. There are one-, two-, or even higher-dimensional arrays. As with scalar variables, arrays are declared in a Dim statement as in... 

The dummy parameters N, Nums, and Avg do not appear in a Dim statement. They inherit the data type and structure of the actual argument when the subroutine is called. The calling statement in the next two examples is... 

The anonymous Dim statement allows anything to be assigned to the associated variables. 

Arrays. An important programming requirement for many scientific-type calculations is the ability to subscript variables, and the use of arrays in computer programming is a way to meet that requirement. The most common variables in scientific calculations are one-dimensional, jc, [syntax x (i) ] and two-dimensional, [syntax x (i, j) ], but larger multidimensional arrays also are possible. The dimension of the array is always given using a dim statement in one of the first few lines of the program (illustrated below) this allows the computer to set aside memory for the array. The... 

The first step in the file routine opens a specific file with the name "myFile". The routine will search the folder with the program for this file. If the file does not exist, the routine will create it. The "R" designates that this is a random file for input and output. Other designations are "i" for input only, "O" for output only, and "A" for append (which positions the pointer at the end of the file). The "1" in the open statement is the file ID number. This allows more than one file to be opened at the same time. The write 1 statement indicates that the variables following the write 1 statement are to be written to file 1. The close 1 statement closes file 1. This routine will save the 45 values of G as specific records in a file, named "oyFile", in a folder on the disk where the program is found. The DIM statement is necessary because G is an array. 

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