Count consonants in a string (Iterative and recursive methods)
Last Updated :
20 Feb, 2023
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Given a string, count total number of consonants in it. A consonant is an English alphabet character that is not vowel (a, e, i, o and u). Examples of constants are b, c, d, f, and g.
Examples :
Input : abc de Output : 3 There are three consonants b, c and d. Input : geeksforgeeks portal Output : 12
1. Iterative Method
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C++
// Iterative CPP program to count total number // of consonants #include <iostream> using namespace std; // Function to check for consonant bool isConsonant(char ch) { // To handle lower case ch = toupper(ch); return !(ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U') && ch >= 65 && ch <= 90; } int totalConsonants(string str) { int count = 0; for (int i = 0; i < str.length(); i++) // To check is character is Consonant if (isConsonant(str[i])) ++count; return count; } // Driver code int main() { string str = "abc de"; cout << totalConsonants(str); return 0; } |
Java
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Output
3
Time Complexity: O(n), where n is the length of the string
Auxiliary Space: O(1)
2. Recursive Method
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C++
// Recursive CPP program to count total number // of consonants #include <iostream> using namespace std; // Function to check for consonant bool isConsonant(char ch) { // To handle lower case ch = toupper(ch); return !(ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U') && ch >= 65 && ch <= 90; } // to count total number of consonants from // 0 to n-1 int totalConsonants(string str, int n) { if (n == 1) return isConsonant(str[0]); return totalConsonants(str, n - 1) + isConsonant(str[n-1]); } // Driver code int main() { string str = "abc de"; cout << totalConsonants(str, str.length()); return 0; } |
Java
Python3
C#
Javascript
Output
3
Time Complexity: O(n), where n is the length of the string
Auxiliary Space: O(n), due to recursive call stacks.
Illustration of recursive method:
