165. Compare Version Numbers.c

/*
165. Compare Version Numbers

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

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

intcompareVersion(char*version1, char*version2) {
    inta, b;
    char*v1, *v2;
    while (version1||version2) {
        if (version1) {
            v1=version1;
            version1=strchr(version1, '.');
            if (version1) {
                *version1=0;
                version1++;
           }
            a=atoi(v1);
       } else {
            a=0;
       }
        if (version2) {
            v2=version2;
            version2=strchr(version2, '.');
            if (version2) {
                *version2=0;
                version2++;
           }
            b=atoi(v2);
       } else {
            b=0;
       }
        if (a>b) return1;
        if (a<b) return-1;
   }
    
    return0;
}


/*
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*/