在String比较期间将String.charAt减少到一个循环

Question

I need to compare two strings that are of varying length and as such I have written two conditional loops depending on which String is longest:

boolean compare(String first, String second)  
{  
   boolean firstLongest = first.length() > second.length();  
   if(firstLongest)  
      {
         for(int i = 0; i < first.length(); i++)  
             //charAt code here  
       }
    else{   
            for(int i = 0; i < second.length();i++)  
              //charAt code here
         }  

}

I decided to re-write it as so:

boolean compare(String first, String second)  
    {  
       int lengthDifference = first.length() - second.length(); 
       for(int i = 0; i < first.length() + lengthDifference;i++)  
         //charAt code here    
    }

I want to avoid having 1) two loops and 2) out of bounds exceptions. My question is does the above implementation have a corner case that I am missing or should this work for all possible inputs.

Answer 1

Your revised version will break if the second string is longer.

Use:

int combinedLength = Math.min(first.length(), second.length());

then your condition only needs to be:

i < combinedLength

Answer 2

Simply use the lowest one:

//Maybe knowing what the length diff is interesting to achieve your goal:
int lenDiff = Math.abs(first.length() - second.length());

// The loop, taking the length of the shortest one as limit
for (int i = 0; i < Math.min(first.length(), second.length()); ++i)
{
    // Char code here
}