a question that i can't solve

Write a program that can count the number of the alphabet from the string.
Example string " Complicated Question"

I need a index.

Code:

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char string[50] = " Complicated Question";
string = tolower((unsigned char)string);
int alpha[26];
int i;
for (i=0; i<50; i++) {
    alpha[string[i]-97]++;
}

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Took < 5mins. Something like that anyway. Now you have to modify that to use pointers, to improve. BTW, the number of times each character occurs is stored in alpha (u can figure out how to access each element.

P4R4N01D: What is 32 - 97, and where in your 26 element array is that? Perhaps "isalpha" would be useful inside your loop?

Code:

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for (i=0; i<50; i++) {

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Perhaps 50 should be replaced with the length of the string?


--
Mats

Code:

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string = tolower((unsigned char)string);

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Also, tolower() takes a single character (as an int), not a whole string.

Took < 5 secs to find some bugs. :)

Quote:

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Originally Posted by cpjust

Code:

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string = tolower((unsigned char)string);

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Also, tolower() takes a single character (as an int), not a whole string.

Took < 5 secs to find some bugs. :)

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std::transform(s.begin(), s.end(), s.begin(), tolower);

Quote:

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Originally Posted by EOP

std::transform(s.begin(), s.end(), s.begin(), tolower);

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True, but this is the C forum :)

QuantumPete

P4R4N01D has the right idea, it's all about ascii values. But you guys are getting bogged down with unnecessary bonus functions:

Code:

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#include <stdio.h>

int main(int argc, char *argv[]) {
        short int cv, i=0, total=0;
        while (argv[1][i] != 0) {        // change to lowercase
                if ((argv[1][i] > 64) && (argv[1][i] < 91)) argv[1][i]+=32;
                if ((argv[1][i] < 97) || (argv[1][i] > 122)) {
                        i++;                // skip non-letters
                        continue;
                }
                cv = argv[1][i]-96;
                total += cv;
                i++;
        }
        printf("%s = %d\n", argv[1],total);
}

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gcc -o kabblah kabblah.c
./kabblah "Complicated Question"
complicated question = 221

The OP needed this converted to use pointers not array indexing. Also this issue is very similar to strlen() and there are numerous examples on the web on how to do just that. Is there any benefit to setting tolower when you only need to check the count of letters within the string?

Also working with the ACII table is very good when checking if it us upper case or not and doing the appropriate math to convert if necessary.

Quote:

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Originally Posted by slingerland3g

The OP needed this converted to use pointers not array indexing. Also this issue is very similar to strlen() and there are numerous examples on the web on how to do just that. Is there any benefit to setting tolower when you only need to check the count of letters within the string?

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You should probably re-read what the OP is asking for. To count the number of times each letter of the alphabet appears in a given string.

QuantumPete

Was the below requirment changed? As I did not catch that....

"Write a program that can count the number of the alphabet from the string."

Ah, I see the problem. Lol, if the OP has the "C Programming" book, by any chance, this is covered pretty well, if I remember correctly, in order to check if a letter of the alphabet is found and thus increments the array element.

Actually, considering that I have met quite a few people who confuse "letter" and "alphabet", it could be the case that the OP is asking how to count the number of letters in a string.

Quote:

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Originally Posted by laserlight

Actually, considering that I have met quite a few people who confuse "letter" and "alphabet", it could be the case that the OP is asking how to count the number of letters in a string.

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Hmm, true, I guess it will be a moot point if the OP doesn't come back to clarify what he meant...

QuantumPete

Quote:

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Originally Posted by MK27

P4R4N01D has the right idea, it's all about ascii values. But you guys are getting bogged down with unnecessary bonus functions:

gcc -o kabblah kabblah.c
./kabblah "Complicated Question"
complicated question = 221

---

Quote:

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Originally Posted by slingerland3g

The OP needed this converted to use pointers not array indexing. Also this issue is very similar to strlen() and there are numerous examples on the web on how to do just that. Is there any benefit to setting tolower when you only need to check the count of letters within the string?

Also working with the ACII table is very good when checking if it us upper case or not and doing the appropriate math to convert if necessary.

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Sure, as long as you don't mind throwing portability out the window.
If the whole world used ASCII & spoke English, there would be no more problems right? ;)

This may not be exactly what the OP needed but though I would try to remember the solution from the book, just do not have it on hand but it went something like this:

Usage:

./countLetters "count my letters"

Code:

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#include <stdio.h>

int main(int argc, char **argv) {
int i;
int letters[26] = {0};
char ch = 'a';

while (*(argv[1]))
{
 letters[(*(argv[1])++) - 'a']++;
}

printf ("Letters found are: \n");

for (i = 0 ; i < 26 ; i++)
{
  printf ("%c = %d \n", ch++, letters[i]);
}
}

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Does the book lack proper indentation too? :p

That was a first draft, the main purpose was to give the original poster an idea on how the qn could be solved. Also the OP didn't make much sence so I took it as count the number of times each letter occurs w/n the string. Also I could not be bothered counting the characters w/n the string, so just chose an arbitary number instead, still works.
In response to tolower: woops, that can be corrected, but one can still guess what I was trying to do. Still hope it helps w/ understanding.