Valid Number

Validate if a given string is numeric.

Examples:

• "0" => true
• " 0.1 " => true
• "abc" => false
• "1 a" => false
• "2e10" => true

Return 0 / 1 ( 0 for false, 1 for true ) for this problem

Clarify the question using “See Expected Output”

• Is 1u ( which may be a representation for unsigned integers valid?
  For this problem, no.

• Is 0.1e10 valid?
  Yes

• -01.1e-10?
  Yes

• Hexadecimal numbers like 0xFF?
  Not for the purpose of this problem

• 3. (. not followed by a digit)?
  No

• Can exponent have decimal numbers? 3e0.1?
  Not for this problem.

• Is 1f ( floating point number with f as prefix ) valid?
  Not for this problem.

• How about 1000LL or 1000L ( C++ representation for long and long long numbers )?
  Not for this problem.

• How about integers preceded by 00 or 0? like 008?
  Yes for this problem