Compare Version Numbers

标签：string

Compare two version numbers version1 and version2.
If version1 > version2 return 1, if version1 < version2 return -1, otherwise return 0.

You may assume that the version strings are non-empty and contain only digits and the . character.
The . character does not represent a decimal point and is used to separate number sequences.
For instance, 2.5 is not "two and a half" or "half way to version three", it is the fifth second-level revision of the second first-level revision.

Here is an example of version numbers ordering:

0.1 < 1.1 < 1.2 < 13.37

#include<iostream>
#include<string>
#include<vector>
using namespace std;
//转化为整数再比较
int compareVersion(string version1, string version2) {
	
	int value1 = 0,value2 = 0;
	int index1=0,  index2 = 0;
	while (index1<version1.size()||index2<version2.size())
	{
		value1 =0;
		value2 =0;
		while (index1<version1.size())
		{
			if (version1[index1]=='.')
			{
				index1++;
				break;
			}
			value1 = 10*value1+version1[index1]-'0';
			index1++;
		}
		while (index2<version2.size())
		{
			if (version2[index2]=='.')
			{
				index2++;
				break;
			}
			value2 = 10*value2+version2[index2]-'0';
			index2++;
		}
		if (value1>value2)
			return 1;
		if (value2>value1)
			return -1;
	}
	return 0;
}

Compare Version Numbers

标签：string

原文地址：http://blog.csdn.net/li_chihang/article/details/44775241