According to one source I found regarding the %e format specifier in printf:
Which seems to be echoed in another post here.The exponent always contains at least two digits; if the value is zero, the exponent is 00. In Windows, the exponent contains three digits by default, e.g. 1.5e002, but this can be altered by Microsoft-specific _set_output_format function.
So, assuming you are indeed on a Windows system maybe you could use the suggestion. Otherwise it looks like you can't do it... except maybe by printing it to a string and then finding/deleting those extra 0's and then printing the modified string.