Keeping it simple. Once you've got the mantissa and exponent out, you can check your number is in range by a simple check that the exponent is within range.
For a 32 bit signed integer the limit is 2E9. This means that the exponent is fine 0-8, or if the exponent is 9, then only if the mantissa is 1 or 2. This only works with a single digit mantissa.
For adding more digits to the mantissa, while a robust range check can be done, it gets more complicated. String-to-Integer functions are very conservatively written pieces of code designed to be quick.
Keeping it simple. Once you've got the mantissa and exponent out, you can check your number is in range by a simple check that the exponent is within range.
For a 32 bit signed integer the limit is 2E9. This means that the exponent is fine 0-8, or if the exponent is 9, then only if the mantissa is 1 or 2. This only works with a single digit mantissa.
For adding more digits to the mantissa, while a robust range check can be done, it gets more complicated. String-to-Integer functions are very conservatively written pieces of code designed to be quick.