C#Script, C++Script - Working With Numeric Values

Basics

Language-specific operations

Rounding off

Division operations

Converting to strings

Getting numerical values from strings

The numeric values can be of integer and floating-point type and the TestComplete scripting engine does not distinguish floating-point and integer data types, so the same variable can hold the values of both types.

The integer value can accept zero, positive and negative numbers within the ±1.7976931348623157x10^308 range. Generally the integer number is considered to be in decimal numeration, however the octal or hexadecimal representation is also possible.

The octal and hexadecimal numbers can be negative, but cannot be written in the exponential form or cannot have a fractional part.

The integer is treated as octal if it is prefixed with zero and contain digits from 0 to 7. For instance, 061 is equivalent to decimal 49. The integer is treated as hexadecimal if it is prefixed with zero followed by letter "x" (uppercased or lowercased) and contain digits from 0 to 9 or letters from A to F (uppercased or lowercased). The letters from A to F are used to represent numbers from 10 to 15. For instance, 0xff is equivalent to decimal 255 and 0x5EA is equivalent to decimal 1514.

Floating-point numbers have a fractional part that can be as small as ±5x10^-324. Generally, the fractional part is separated by the decimal point character. For example, 123.456. Another possible notation for the floating point value is scientific or exponential notation. In this notation the exponent symbol "e" means "ten to the power of". For example, 37e2 is a scientific notation for 3700.

The aqConvert and aqString objects contain several methods that can be helpful when working with numeric values. The tables below list those methods. The objects are available for all supported scripting languages, so that you can use them to operate with date values regardless of the chosen language.

To perform mathematical operations over numbers, C#Script and C++Script have its own inherent object Math. The object contains properties and methods that correspond to some frequently used constants and mathematical operations. The table below lists the properties and methods of the Math object. For a detailed description, see the documentation on the Math object in the MSDN library.

C#Script and C++Script also have some additional arithmetic operations:

This sample code illustrates how to use them:

C#Script and C++Script have three routines that accept a floating point value and return an integer value, but each of them has it’s own specifics These routines are: floor, ceil and round.

The floor routine always returns the integer value that is smaller than the input value, or in other words it rounds down the input value. It does not distinguish whether the input value is positive or negative. That is, for 0.5 the routine will return 0, and for -0.5 it will return -1.

The ceil routine is similar to floor, but it always returns the integer value that is greater than the input value, or in other words it rounds up the input value. Like the former routine, it does not distinguish whether the input value is positive or negative. For 0.5 the routine will return 1, and for -0.5 it will return 0.

The round routine implements the most common method of rounding, that is also known as symmetric arithmetic rounding. It returns the nearest integer that corresponds to a given floating-point value. If the fractional part of an input value is equal to or greater than 0.5, then the resulting integer is greater than the input value, otherwise - the result is less than the input value. This rule applies to positive numbers, the same rule is also applied to negative numbers, but with one difference - the absolute values are used instead of actual input values. That is, for 0.4 the routine will return 0, for 0.5 it will return 1, and for -0.5 it will return -1.

Here is a sample that demonstrates the specifics of rounding with those methods:

The standard operation of division that is performed by the / operator, generally returns a floating-point result. The returned result (quotient) can be integer only when the first operand (dividend) is evenly divisible by the second operand (divider), or in other words is divided without a remainder (modulo). However sometimes we need to get an integer quotient for the numbers which are not evenly divisible. Such an operation is called integer division. There are two ways to perform integer division in C#Script and C++Script: the first is to calculate a result of a standard division and then round it off to integer, the second way is to calculate the modulo with the % operator, subtract it from the dividend and then perform the division. Both techniques can be used, but for the large number of operations, it is better to use the second one, because it takes less time to run.

The code fragment below gives an implementation for each of the described techniques:

One of the most frequent actions over numbers is converting them to strings. This could be required to post a numerical value to the TestComplete log, output the test result, write data to a text file and in many other situations. For this purposes, aqConvert has two methods: IntToStr and FloatToStr. You can also find the Format method of the aqString object useful.

IntToStr accepts an integer value and returns a string holding its decimal representation. The integer values can be in decimal, octal or hexadecimal form, but the resulting string is always in the decimal form.

To convert floating-point numbers, use the FloatToStr or Format method. The FloatToStr is the simplest: the generated string contains up to 15 digits and the decimal separator is only displayed when required. To specify the format of the resulting string, use the Format method. It provides great flexibility, since it allows you to set a user-defined formatting string.

The code below illustrates how to use these methods.

The aqConvert object has three methods that convert a string to a number. They are StrToInt, StrToInt64 and StrToFloat.

The StrToInt and StrToInt64 methods accept a string holding a decimal representation of a number and return an integer. The input string can contain only digits and the + or - sign. All other symbols are not allowed. If the input string does not hold a valid integer an exception occurs.

To get a floating-point number from a string use the StrToFloat method - it accepts a string that consists of digits, decimal separator, "+" or "-" symbols and mantissa ("e" or "E" character followed by a positive or negative integer) and returns the floating-point number. If the input string does not hold a floating-point number an exception occurs.

Here is a sample that shows how to use those methods:

However, sometimes, the functionality of these methods is insufficient, since they have some drawbacks when working with arbitrary strings. StrToInt, StrToInt64 and StrToFloat methods cannot recognize strings containing characters other than those mentioned above. If these methods cannot recognize the string, they raise an exception.

A versatile routine that would extract numbers from any textual string and recognize both integer and floating point values can be implemented with the help of regular expressions. The following regular expression pattern would match positive or negative integer numbers, as well as floating-point numbers both in general and scientific notations: [-+]?\d*\.?\d+([eE][-+]?\d+)?.

Here is a sample for the routine that verifies whether a string contains a number. It uses the regular expression to check the input string and returns True if the input string holds an integer or floating point number.

The same regular expression can be used to extract the number from a string. Since the input string can contain more than one number matching the regular expression, only the first occurrence would be returned by the routine. If the string does not hold any number, it is convenient to set the default value that would be returned in this case.

Here is an example of how to use those two routines: