Need an Algorithm

[Cedric Moonen]

Maybe something like that:

int Number = 57; // For example
char szString[255];
strcpy(szString,"");

while (true)
{
if (Number>=27)
{
strcat(szString,"a");
Number -= 26;
}
else
{
char Temp;
Temp = Number + 97; // 97 is the ASCII code for 'a'
int StrLen = strlen(szString);
szString[StrLen] = Temp;
szString[StrLen+1] = '\0';
break; //end while loop
}
}

Ok, I didn't tested it so there could be some mistakes but this gives you the general idea

[toxcct]

you code won't work because you consider that if (Number>=27) only... but if Number == 53, the result must be "ba", etc... as P-Rex said, there are until "zzzz" possibilities, that means 26^4 = 456976 cases...

---

TOXCCT >>> GEII power
[toxcct][VisualCalc]

[Andrew Kirillov]

CString str; int number = 53; do { number--; str.Insert(0, 'a' + (number % 26)); number /= 26; } while (number > 0); TRACE(_T("str: %s"), str);

[toxcct]

int iVal = 453; // For example
char Result[5] = "";

if (iVal >= 17577) { // For the most left character
Result[0] = (iVal % 26) - 1 + 'A';
}
else {
Result[0] = '\0';
}

if (iVal >= 677) { // For the second left character
Result[1] = (iVal % 26) - 1 + 'A';
}
else {
Result[1] = '\0';
}

if (iVal >= 27) { // For the third left character
Result[2] = (iVal % 26) - 1 + 'A';
}
else {
Result[2] = '\0';
}

if (iVal >= 1) { // For the most right character
Result[3] = (iVal % 26) - 1 + 'A';
}
else {
Result[3] = '\0';
}

Result[4] = '\0';

// Re-order the string (erases the '\0' at the beginning of the string)...
for (int i = 0, i < 4, i++) {
if (Result[1] == '\0') {
Result[i] = Result[i+1];
}
}

i didnot tested however... :cool:

---

TOXCCT >>> GEII power
[toxcct][VisualCalc]

[Cedric Moonen]

I think you didn't understand completely my code ;) For exemple if Number == 53, the result must be "ab" and not "ba". Thus in my code, if (Number >= 27), I DON'T jump out of the loop but comes once again in the loop, thus adding 'b' to the already existing string (that contains 'a'). Is it a little bit clearer ? [EDIT] Sorry, I don't add 'b' but 'z' because 53-27 = 26 that corresponds to 'z' :) [EDIT2] After 2 minutes of reflexion, I see that there effectively a problem in the code :~ . There will only be 'a' in the begining of the string... I must not subtract but rather divide by 26... But I think the other solutions are good

[P Rex]

Thanks, you are my hero. I didn´t thought that this is so easy :-D Pascal

[Tim Smith]

As he properly realized, going from a number to a 'A' to 'ZZZZ' representation is the same as printing the number base 26 where the digits are the letters 'A' - 'Z'. If you wanted to write a number converter to print that value as decimal, then just change the / 26 to / 10 and the initial character from 'A' to '0'. Tim Smith I'm going to patent thought. I have yet to see any prior art.

[Blake Miller]

What value is represented by '0' ? If you know that, then you have a base 26 system. See, everything goes up to 26, then it carries over one place. You are just mapping a base 26 numeric system to letters.

[Blake Miller]

:wtf:

[toxcct]

Blake Miller wrote: :wtf: what ?:confused:

---

TOXCCT >>> GEII power
[toxcct][VisualCalc]

[camoguard]

You sound like you have it. But in case you haven't thought of this, you can imagine you are working with a base 27 system of numbers and you are converting from decimal. Begin by checking if your value is greater than (27^3+1) if it is get the mod of your input number by (27^3+1 because a is 1), that's your first digit which falls between 0 and 26. then subtract that number off your working total. Then check if the remainder is bigger than (27^2+1). If it is, then mod by (27^2+1), that's your second digit. And so on. Since you are working with a-z just add the value of the char('a') to each mod and save yourself a switch statement. One for loop of four iterations should do it.

[Alton Williams]

Dosen't work toxcct