Question

How to count alphabetic character occurrences in a string with C++

Answer 1

#include <iostream>
#include <string>
 
using std::cout;
using std::endl;
 
int main()
{
    int letters[26] = {0};
    std::string s = "c++ programming";
 
    for (int i = 0; i < s.length(); i++) {
        if (isalpha(s[i])) {
            letters[s[i] - 'a']++;
        }
    }
 
    for (int i = 0; i < 26; i++) {
        if (letters[i] != 0) {
            cout << (char)('a' + i) << ": " << letters[i] << endl;
        }
    }
}
 
 
 
/*
run:
 
a: 1
c: 1
g: 2
i: 1
m: 2
n: 1
o: 1
p: 1
r: 2

*/

 

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Answer 2

#include <iostream>
#include <cctype> 

void countLetterOccurrences(const char* str) {
    int counts[26] = {0}; // Array to store counts of each letter

    // Traverse the character array
    for (int i = 0; str[i] != '\0'; ++i) {
        if (std::isalpha(str[i])) { // Check if the character is a letter
            char lowerChar = std::tolower(str[i]); // Convert to lowercase
            counts[lowerChar - 'a']++; // Increment the count for the letter
        }
    }

    for (int i = 0; i < 26; ++i) {
        if (counts[i] > 0) {
            std::cout << static_cast<char>('a' + i) << ": " << counts[i] << std::endl;
        }
    }
}

int main() {
    const char* str = "C++ Programming";
    
    countLetterOccurrences(str);
}


/*
run:

a: 1
c: 1
g: 2
i: 1
m: 2
n: 1
o: 1
p: 1
r: 2

*/

 

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