String Manipulation in LoadRunner

I think that the following question from the Mercury Support forum neatly illustrates one of the major problems with LoadRunner.

Hi all,

I have a financial application that submits the data in $ amounts. When I looked in the extended log the value is in number format like (43251) but during submission it is converted into dollar format $43,251.00.

How to convert the string into $ format? Is there any function?

Thanks in advance,

The majority of people using LoadRunner aren’t great programmers, and the ones who are aren’t necessarily great programmers in C. Fortunately, the level of skill required for most problems is not very high, and everyone muddles along as best they can.

Not surprisingly, the small proportion of problems that require more than basic knowledge of C are done poorly (or by someone else).

The most common problem that requires additional programming is basic string manipulation. Most LoadRunner scripts are written in C, and manipulating strings with C is like pulling teeth.

I would argue that Mercury’s choice to use C as LoadRunner’s main scripting language, while having the advantages of it being a solid standard, having a low performance overhead, and there being a large pool of people at least partially familiar with the language, has the unfortunate trade-off of it being…well…kind of hard for most people.

Here’s my solution to the above problem.

// This function converts a numeric string to a dollar value.
// eg. 123456 becomes $123,456.00
LPCSTR ConvertStringToDollars(char input[20]) {
    int i;
    // To account for the extra characters that will be added, the size of output
    // should be 4 + strlen(input) + (strlen(input)/3)
    char output[30];

    strcpy(output,"$");

    // insert a comma every third character, but not at the start.
    for (i=0; i<strlen (input); i++) {
        if ( ((strlen(input)-i)%3==0) && (i!=0) ) {
            output[strlen(output)] = ′,′;
        }
        output[strlen(output)] = input[i];
    }

    strcat(output, ".00");

    return output;
}

Action()
{
    lr_output_message(ConvertStringToDollars("123456")); // Prints "$123,456.00"
    return 0;
}

This illustrates my point perfectly. Even though the code performs a simple operation, it’s complicated, and requires knowledge of how C stores data in memory in order to implement. Possibly more importantly, implementing the solution in C takes a lot longer than it might in another language. If there are any mistakes in my code, it just proves my point even more.

As computers increase in power and the performance advantage of writing performance test scripts in C shrinks even further compared to other languages, the relative disadvantages of C will grow in the minds of testers.