Compare two version numbers version1 and version1.
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

Credits:
Special thanks to @ts for adding this problem and creating all test cases.

#include<stdio.h>
#include<string.h>

int compareVersion(char *version1, char *version2) {
    int i , j , k , data1 = 0 , data2 = 0;
    for(i = 0,j = 0; version1[i] != '\0' && version2[j] != '\0';){
        if(version1[i] == '.' && version2[j] == '.'){
            if(data1 > data2) return 1;
            if(data1 < data2) return -1;
            data1 = 0;
            data2 = 0;
            i++;
            j++;
        }
        else if(version1[i] != '.' && version2[j] == '.') {
            while(version1[i] != '.' && version1[i] != '\0'){
                data1 = data1*10 + version1[i]-'0';
                i++;
            }
            if(version1[i]=='\0') break;
        }
        else if(version1[i] == '.' && version2[j] != '.') {
            while(version2[j] != '.' && version2[j] != '\0'){
                data2 = data2*10 + version2[j]-'0';
                j++;
            }
            if(version2[j]=='\0') break;
        }
        else{
            data1 = data1*10 + version1[i]-'0';
            data2 = data2*10 + version2[j]-'0';
            i++;
            j++;
        }
    }
    if(version1[i] == '\0' && version2[j] != '\0') {
        if(version2[j] == '.' ) {
            k=j+1;
            if(data1 > data2) return 1;
            if(data1 < data2) return -1;
            if(data1 == data2) data1 = 0;
        }
        else k=j;
        if(version2[k-1] == '.') data2 = 0;
        while(version2[k] != '\0' && version2[k] != '.'){
            data2 = data2*10 + version2[k]-'0';
            k++;
        }
    }
    else if(version1[i] != '\0' && version2[j] == '\0') {
        if(version1[i] == '.' ) {
            k=i+1;
            if(data1 > data2) return 1;
            if(data1 < data2) return -1;
            if(data1 == data2) data2 = 0;
        }
        else k=i;
        if(version1[k-1] == '.') data1 = 0;
        while(version1[k] != '\0' && version1[k] != '.'){
            data1 = data1*10 + version1[k]-'0';
            k++;
        }
    }
    if(data1 > data2) return 1;
    if(data1 < data2) return -1;
    if(data1 == data2) return 0;
}

void main(){
    printf("%d\n",compareVersion("1.0","13.37"));
}

Compare Version Numbers