[One question per day] Find the longest continuous number string (string, greedy) in the string

Question source
Niuke.com
Link: Find the longest continuous number string in the string

Title description
Read in a string str, output the longest continuous number string in the string str

Enter a description:

The test input contains 1 test case, a string str, and the length does not exceed 255.

Output description:

Output the longest continuous number string in str in one line.

enter:

abcd12345ed125ss123456789

Output:

123456789

The problem-solving idea is to
traverse the string and use cur to record the continuous number string. If it is not a number character, it means that a continuous number string is over, then the number string is compared with the previous number string, if it is longer, then update The longer number string is updated to res.

Code display

#include <iostream>
#include <string>
using namespace std;

int main()
{
    
    
	string str,res,cur;
	cin >> str;
	for(int i = 0;i <= str.length();i++)
	{
    
    
		if(str[i] >= '0' && str[i] <= '9')
		{
    
    
			cur += str[i];
		}
		else
		{
    
    
			if(res.size() < cur.size())
				res = cur;
			else
				cur.clear();
		}
	}
	cout << res;
	return 0;
}