Where is wrong??

[Andreik]

I try to write this _Distance() function to C and work but result is different, what problem could be?

My C code:

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extern "C" __declspec(dllexport) float _Distance(char *str1, char *str2, int maxoffset){
    float result;
    int len1 = strlen(str1);
    int len2 = strlen(str2);
    if ((len1 * len2) == 0)
    {
        return (float)len1 + (float)len2;
    }
    int c = 0;
    int offset1 = 0;
    int offset2 = 0;
    int dist = 0;
    while (((c + offset1) < len1) && ((c + offset2) < len2)){
        if (str1[c + offset1 + 1] != str2[c + offset2 +1]){
            offset1 = 0;
            offset2 = 0;
            for (int index = 0; index < maxoffset; ++index){
                if ((c + index < len1) && (str1[c + index + 1] == str2[c + 1])){
                    if (index > 0){
                        dist += 1;
                        offset1 = index;
                    }
                    dist -= 1;
                    break;
                }
                if ((c + index < len2) && (str1[c + 1] == str2[c + index + 1])){
                    if (index > 0){
                        dist += 1;
                        offset2 = index;
                    }
                    dist -= 1;
                    break;
                }
            }
            dist += 1;
        }
        c += 1;
    }
    result = (float)dist + ((float)len1 - (float)offset1 + (float)len2 - (float)offset2) / 2 - (float)c;
    return result;
}

[martin]

I try to write this _Distance() function to C and work but result is different, what problem could be?

My C code:

expandcollapse popup

extern "C" __declspec(dllexport) float _Distance(char *str1, char *str2, int maxoffset){
    float result;
    int len1 = strlen(str1);
    int len2 = strlen(str2);
    if ((len1 * len2) == 0)
    {
        return (float)len1 + (float)len2;
    }
    int c = 0;
    int offset1 = 0;
    int offset2 = 0;
    int dist = 0;
    while (((c + offset1) < len1) && ((c + offset2) < len2)){
        if (str1[c + offset1 + 1] != str2[c + offset2 +1]){
            offset1 = 0;
            offset2 = 0;
            for (int index = 0; index < maxoffset; ++index){
                if ((c + index < len1) && (str1[c + index + 1] == str2[c + 1])){
                    if (index > 0){
                        dist += 1;
                        offset1 = index;
                    }
                    dist -= 1;
                    break;
                }
                if ((c + index < len2) && (str1[c + 1] == str2[c + index + 1])){
                    if (index > 0){
                        dist += 1;
                        offset2 = index;
                    }
                    dist -= 1;
                    break;
                }
            }
            dist += 1;
        }
        c += 1;
    }
    result = (float)dist + ((float)len1 - (float)offset1 + (float)len2 - (float)offset2) / 2 - (float)c;
    return result;
}

One error is

for (int index = 0; index < maxoffset; ++index){

which should be

for (int index = 0; index <= maxoffset; ++index){

There could be others.

[Andreik]

One error is

for (int index = 0; index < maxoffset; ++index){

which should be

for (int index = 0; index <= maxoffset; ++index){

There could be others.

This shouldn't be an error. AutoIt code is:

For $i = 0 to $maxOffset - 1

For maxoffset equal with 5 the range is 0-4.

In my C code:

for (int index = 0; index < maxoffset; ++index){

Variable index should be < then maxoffset (equal with 5) so the range is 0-4.

Am I missing something?

[martin]

This shouldn't be an error. AutoIt code is:

For $i = 0 to $maxOffset - 1

For maxoffset equal with 5 the range is 0-4.

In my C code:

for (int index = 0; index < maxoffset; ++index){

Variable index should be < then maxoffset (equal with 5) so the range is 0-4.

Am I missing something?

Sorry Adreik, somehow I couldn't see that -1.

Can you give an example of two strings that give different answers in each version?

EDIT: Maybe this is it. In the autoit version the strings are parsed from the first character which is element 1, but in C they start at 0 so you are 1 position out in various places.

For Example

in AutoIt there is

If (($c + $i < $ls1) And (StringMid($s1, $c + $i + 1, 1) = StringMid($s2, $c + 1, 1))) Then

so in C you should have

if ((c + index < len1 - 1) && (str1[c + index] == str2[c])){

which is not what you wrote.

Edited October 17, 2009 by martin

[Andreik]

EDIT: Maybe this is it. In the autoit version the strings are parsed from the first character which is element 1, but in C they start at 0 so you are 1 position out in various places.

Yes, you are right. I tried and get good results. Thanks for help.

Regards,

Andreik