BUG: ROUND() Function Not Rounding Properly After Calculations

RESOLUTION

Use the Currency data type when more accurate rounding of numeric values is necessary. However, using the Currency data type does not fix all rounding problems.

The following code example provides a workaround by converting the numeric contents of mpay to a string. Then the VAL() function converts the string back to a numeric data type for use in the ROUND() function.

   CLEAR
   mrate = 86.173125
   mhours = 24.0000
   mpay = mhours * mrate
   ? mpay
   test=STR(mpay,LEN(STR(mpay)),LEN(STR(mpay)))
   ? ROUND(mpay, 2)
   ? ROUND(VAL(test),2)
				

The code first returns the value of mpay. Next the incorrectly rounded value, followed by the correctly rounded value, appears. The above code may produce the correct result with every occurrence of rounding errors in Visual FoxPro.

The discrepancy of the ROUND() function's behavior is often related to a decrease in precision as Visual FoxPro performs calculations on several numbers. For instance, by placing the value of the variable mpay, 2068.1550000000, directly into the ROUND() function, the correct result appears. Type the following in the Command window: The correct value appears.