Operation of WPP[edit] WPP is run prior to compilation (in other words, before even the C preprocessor), and generates a trace message header for each file that it processes (by default this header is filename.tmh, where filename is the name of the processed source file). WPP's understanding of C/C++ syntax is very limited.
Divide the new value by the old value and multiply by 100 to find the absolute relationship between the two values. A process that is similar (but not identical) to the process used to find percent change is that used to find the absolute percentage relationship between the old and new values.
How to Calculate. 1  Percentage Change: a positive value is an increase, a negative value is a decrease. 2  Percentage Error: ignore a minus sign (just leave it off), unless you want to know if the error is under or over the exact value. Percentage Difference: ignore a minus sign, because neither value is more important, so being above or below does not make sense. Step 4: Convert this into a percentage (multiply by 100 and add a % sign) The Formulas (Note: the | symbols mean absolute value, so negatives become positive.) Percent Change = New Value â Old Value|Old Value| Ã 100%