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Count the number of occurrences of each letter in a string

How can I count the number of occurrences in c of each letter (ignoring the case) in a string? To print letter: # number of occurences, I have a code to count the occurrence of a single letter, but how can I calculate the presence of each letter in a string?

{
    char
    int count = 0;
    int i;

    //int length = strlen(string);

    for (i = 0; i < 20; i++)
    {
        if (string[i] == ch)
        {
            count++;
        }
    }

    return count;
}

exit:

a : 1
b : 0
c : 2
etc...
+4
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16 answers

Suppose you have a system where there charare eight bits, and all the characters you are trying to count are encoded using a non-negative number. In this case, you can write:

const char *str = "The quick brown fox jumped over the lazy dog.";

int counts[256] = { 0 };

int i;
size_t len = strlen(str);

for (i = 0; i < len; i++) {
    counts[(int)(str[i])]++;
}

for (i = 0; i < 256; i++) {
    printf("The %d. character has %d occurrences.\n", i, counts[i]);
}

, . 100% , ( , , ) , 1. " " , 2. ( 26), - :

#include <ctype.h>
#include <string.h>
#include <stdlib.h>

const char *str = "TheQuickBrownFoxJumpedOverTheLazyDog";

int counts[26] = { 0 };

int i;
size_t len = strlen(str);

for (i = 0; i < len; i++) {
    // Just in order that we don't shout ourselves in the foot
    char c = str[i];
    if (!isalpha(c)) continue;

    counts[(int)(tolower(c) - 'a')]++;
}

for (i = 0; i < 26; i++) {
    printf("'%c' has %2d occurrences.\n", i + 'a', counts[i]);
}
+8

:

int counts[26];
memset(counts, 0, sizeof(counts));
char *p = string;
while (*p) {
    counts[tolower(*p++) - 'a']++;
}

, a z a z, .

, , , tolower a z . tolower(*p) - 'a' 0 25, , .

++ *p, .

+1

26 ints, a-z:

int alphacount[26] = {0}; //[0] = 'a', [1] = 'b', etc

:

for(int i = 0; i<strlen(mystring); i++)      //for the whole length of the string
    if(isalpha(mystring[i]))
        alphacount[tolower(mystring[i])-'a']++;  //make the letter lower case (if it not)
                                                 //then use it as an offset into the array
                                                 //and increment

, A-Z, a-z. , 52 ASCII

+1

, : (IMO, )

  1. /, char . : CHAR_BIT 16 32, bool Used[1 << CHAR_BIT]; . bool Used[1 << CHAR_BIT];

  2. ( size_t int).

  3. ASCII. (Use Upper[])

  4. , char <0. is...() EOF unsigned char

    static const char Upper[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
static const char Lower[] = "abcdefghijklmnopqrstuvwxyz";

void LetterOccurrences(size_t *Count, const char *s) {
  memset(Count, 0, sizeof *Count * 26);
  while (*s) {
    unsigned char ch = *s;
    if (isalpha(ch)) {
      const char *caseset = Upper;
      char *p = strchr(caseset, ch);
      if (p == NULL) {
        caseset = Lower;
        p = strchr(caseset, ch);
      }
      if (p != NULL) {
        Count[p - caseset]++;
      }
    }
  }
}

// sample usage
char *s = foo();
size_t Count[26];
LetterOccurrences(Count, s);
for (int i=0; i<26; i++)
  printf("%c : %zu\n", Upper[i], Count[i]);
}
+1
#include <stdio.h>
#include <string.h>
void main()
{
    printf("PLEASE ENTER A STRING\n");
    printf("GIVE ONLY ONE SPACE BETWEEN WORDS\n");
    printf("PRESS ENETR WHEN FINISHED\n");

    char str[100];
    int arr[26]={0};
    char ch;
    int i;

    gets(str);
    int n=strlen(str);

    for(i=0;i<n;i++)
    {
        ch=tolower(str[i]);
        if(ch>=97 && ch<=122)   
        {
            arr[ch-97]++;
        }
    }
    for(i=97;i<=122;i++)
        printf("%c OCCURS %d NUMBER OF TIMES\n",i,arr[i-97]);   
    return 0;
}
+1

.

main()
{
    int i = 0,j=0,count[26]={0};
    char ch = 97;
    char string[100]="Hello how are you buddy ?";
    for (i = 0; i < 100; i++)
    {
        for(j=0;j<26;j++)
            {
            if (tolower(string[i]) == (ch+j))
                {
                    count[j]++;
                }
        }
    }
    for(j=0;j<26;j++)
        {

            printf("\n%c -> %d",97+j,count[j]);

    }

}

, .

0
#include<stdio.h>
#include<string.h>

#define filename "somefile.txt"

int main()
{
    FILE *fp;
    int count[26] = {0}, i, c;  
    char ch;
    char alpha[27] = "abcdefghijklmnopqrstuwxyz";
    fp = fopen(filename,"r");
    if(fp == NULL)
        printf("file not found\n");
    while( (ch = fgetc(fp)) != EOF) {
        c = 0;
        while(alpha[c] != '\0') {

            if(alpha[c] == ch) {
                count[c]++; 
            }
            c++;
        }
    }
    for(i = 0; i<26;i++) {
        printf("character %c occured %d number of times\n",alpha[i], count[i]);
    }
    return 0;
}
0
for (int i=0;i<word.length();i++){
         int counter=0;
         for (int j=0;j<word.length();j++){
             if(word.charAt(i)==word.charAt(j))
             counter++;
             }// inner for
             JOptionPane.showMessageDialog( null,word.charAt(i)+" found "+ counter +" times");
         }// outer for
0

C :

/* C Program to count the frequency of characters in a given String */

#include <stdio.h>
#include <string.h>

const char letters[] = "abcdefghijklmnopqrstuvwxzy";

void find_frequency(const char *string, int *count);

int main() {
    char string[100];
    int count[26] = { 0 };
    int i;

    printf("Input a string: ");
    if (!fgets(string, sizeof string, stdin))
        return 1;

    find_frequency(string, count);

    printf("Character Counts\n");

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

void find_frequency(const char *string, int *count) {
    int i;
    for (i = 0; string[i] != '\0'; i++) {
        p = strchr(letters, string[i]);
        if (p != NULL) {
            count[p - letters]++;
        }
    }
}
0
#include<stdio.h>

void frequency_counter(char* str)
{
    int count[256] = {0};  //partial initialization
    int i;

    for(i=0;str[i];i++)
        count[str[i]]++;

    for(i=0;str[i];i++) {
        if(count[str[i]]) {
            printf("%c %d \n",str[i],count[str[i]]);
            count[str[i]]=0;
        }
    }
}

void main()
{
    char str[] = "The quick brown fox jumped over the lazy dog.";
    frequency_counter(str);
}
0

, , , . , .

.

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

struct Node { 
    char data; 
    int counter;
    struct Node* next; 
};

void printLinkList(struct Node* head)
{
    while (head != NULL) { 
        printf("\n%c occur %d", head->data, head->counter);
        head = head->next;
    }
}

int main(void) {
    char *str = "!count all the occurances of character in string!";
    int i = 0;
    char tempChar;
    struct Node* head = NULL; 
    struct Node* node = NULL; 
    struct Node* first = NULL; 

    for(i = 0; i < strlen(str); i++)
    {
        tempChar = str[i];

        head = first;

        if(head == NULL)
        {
            node = (struct Node*)malloc(sizeof(struct Node));
            node->data = tempChar;
            node->counter = 1;
            node->next = NULL;

            if(first == NULL)
            {
                first = node;
            }
        }
        else
        {
            while (head->next != NULL) { 
                if(head->data == tempChar)
                {
                    head->counter = head->counter + 1;
                    break;
                }
                head = head->next;
            }

            if(head->next == NULL)
            {
                if(head->data == tempChar)
                {
                    head->counter = head->counter + 1;
                }
                else
                {
                    node = (struct Node*)malloc(sizeof(struct Node));
                    node->data = tempChar;
                    node->counter = 1;
                    node->next = NULL;
                    head->next = node;
                }
            }
        }
    }

    printLinkList(first);


    return 0;
}
0
int charset[256] = {0};
int charcount[256] = {0};

for (i = 0; i < 20; i++)
{
    for(int c = 0; c < 256; c++)
    {
        if(string[i] == charset[c])
        {
           charcount[c]++;
        }
    }
}

charcount .

-1

// JavaScript.

function countWordOccurences()
{
    // You can use array of words or a sentence split with space.
    var sentence = "The quick brown fox jumped over the lazy dog.";
    //var sentenceArray = ['asdf', 'asdf', 'sfd', 'qwr', 'qwr'];
    var sentenceArray = sentence.split(' ', 1000); 
    var output;
    var temp;
    for(var i = 0; i < sentenceArray.length; i++) {
        var k = 1;
        for(var j = i + 1; j < sentenceArray.length; j++) {
            if(sentenceArray[i] == sentenceArray[j])
                    k = k + 1;
        }
        if(k > 1) {
            i = i + 1;
            output = output + ',' + k + ',' + k;
        }
        else
            output = output + ',' + k;
    }
    alert(sentenceArray + '\n' + output.slice(10).split(',', 500));
}

You can see it live --> http://jsfiddle.net/rammipr/ahq8nxpf/
-1

//c- .

void main()
   {
   int i,j; int c[26],count=0; char a[]="shahid";
   clrscr();
   for(i=0;i<26;i++)
    {
        count=0;
          for(j=0;j<strlen(a);j++)
                {
                 if(a[j]==97+i)
                    {
                     count++;
                         }
                           }
                  c[i]=count;
               }
              for(i=0;i<26;i++)
               {
              j=97+i;
          if(c[i]!=0) {  printf("%c of %d times\n",j,c[i]);
                 }
              }
           getch();
           }
-1
protected void btnSave_Click(object sender, EventArgs e)
    {           
        var FullName = "stackoverflow"

        char[] charArray = FullName.ToLower().ToCharArray();
        Dictionary<char, int> counter = new Dictionary<char, int>();
        int tempVar = 0;
        foreach (var item in charArray)
        {
            if (counter.TryGetValue(item, out tempVar))
            {
                counter[item] += 1;
            }
            else
            {
                counter.Add(item, 1);
            }
        }
        //var numberofchars = "";
        foreach (KeyValuePair<char, int> item in counter)
        {
            if (counter.Count > 0)
            {
                //Label1.Text=split(item.
            }
            Response.Write(item.Value + " " + item.Key + "<br />");
            // Label1.Text=item.Value + " " + item.Key + "<br />";
            spnDisplay.InnerText= item.Value + " " + item.Key + "<br />";
        }

    }
-1

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