Find the maximum number present in a String

Given a string with alphabets and numbers. Write an algorithm to find the maximum number in the string. If any number is greater than equal to Max_Value of integer then return the Max_Value.


Input: "abcd 45, 54 and 50 are the numbers"
Output: Maximum Number- 54

Input: aabb123ccdefgh54319hij
Output: 54319

Input: 213123123and544455523412423423424234234234
Output: 2147483647 (Max value of Integer)

Input: abcd
Maximum Number- 0


Recommended Article- String to Integer (AtoI – ASCII to Integer) 

  • Initialize max_so_far=0, current_no=0.
  • Iterate the given string from left to right.
    • If the character is number then start constructing current_no with all the contiguous characters with are number using ASCII to integer conversion. Once get the character which is not a number then update the max_so_far with current_no if max_so_far<current_no and make current_no =0.
    • Keep track of current_no, once it reaches to Max_Value of Integer, return Max_Value.
  • return max_so_far.
  • See and run the code below for more understanding.

Complete Code:


Input: abcd 45, 54 and 50 are the numbers
Maximum Number- 54

Input: aabb123ccdefgh54319hij
Maximum Number- 54319

Input: 213123123and544455523412423423424234234234
Maximum Number- 2147483647

Input: abcd
Maximum Number- 0

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If you find anything incorrect or you feel that there is any better approach to solve the above problem, please write comment.

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