Program to count the number of words, characters, alphabets, vowels, consonants and digit in a line of text

Understanding the problem:

The given question wants us to write an efficient C++ program that takes a string input from the user and displays the number of words, characters, alphabets, vowels, consonants and digits in that given string.

Approaching the problem:

A string is an array of characters, therefore, the number of characters in a string is equal to the string length. Further, we have library functions in C++ to check whether a character is an alphabet or a digit.

An alphabet can either be a vowel or a consonant, so, if an alphabet isn’t a vowel then it is a consonant.

To count the number of words we can check when we encounter a ‘space’ or ‘end of line (\0)’ character. As we encounter any of these we will increment our word count by one.

Algorithm:

1. First, we will input a string from the user and store it in a string variable str.
2. Then we will access str character by character with the help of a for loop
3. First, we will check if the current character is alphabet with the help of “isalpha()” function. If yes we will further use a nested if condition to check if it’s a vowel by comparing it with the five vowels both upper case and lower case.
4. Next, we will check for digit with the help of “isdigit()” function.
5. At last, we will check for ‘space’ and ‘\0’ to count the number of words.

Code:

#include <iostream>
#include <string>	//for using string data type and its functions
#include <cstdio>	//for using getline function
#include <ctype.h >	//for using isalpha, isdigit function
using namespace std;

int main(){
	string str;	//inputting the string and setting all the 
	int words = 0, ch = 0, dig = 0, alph = 0, vow = 0, cons = 0;	// parameters as zero
	cout << "Enter a string\n";
	getline(cin, str);
	ch = str.length();	//setting number of characters equal to the	//string length

	for (int i = 0; i <= str.length(); ++i)	//accessing the string character by character
	{
		if (isalpha(str[i]))	//checking for alphabets
		{ ++alph;
			if (str[i] == 'A' || str[i] == 'a' || str[i] == 'E' || str[i] == 'e' || str[i] == 'I' || str[i] == 'i' || str[i] == 'O' || str[i] == 'o' || str[i] == 'U' || str[i] == 'u')	//checking for vowels
				++vow;
			else
				++cons;	//if not vowel then it must be a consonant
		}
		else if (isdigit(str[i]))	//checking for digits
			++dig;
		if (str[i] == ' ' || str[i] == '\0')	//counting the umber of words
			++words;
	}

	cout << "Number of words=" << words << "\n";
	cout << "Number of alphabets=" << alph << "\n";
	cout << "Number of vowels=" << vow << "\n";
	cout << "Number of consonants=" << cons << "\n";
	cout << "Number of digits=" << dig << "\n";
	cout << "Number of characters=" << ch << "\n";
	return 0;
}

Output

Enter a string
Hello World!
Number of words=2
Number of alphabets=10
Number of vowels=3
Number of consonants=7
Number of digits=1
Number of characters=12