Write a C Program to find frequency of vowels in String using Recursion

Recursion : :

• Recursion is the process of repeating items in a self-similar way. In programming languages, if a program allows you to call a function inside the same function, then it is called a recursive call of the function.

• The C programming language supports recursion, i.e., a function to call itself. But while using recursion, programmers need to be careful to define an exit condition from the function, otherwise it will go into an infinite loop.

• Recursive functions are very useful to solve many mathematical problems, such as calculating the factorial of a number, generating Fibonacci series, etc.

Below is the source code for C Program to find frequency of vowels in String using Recursion which is successfully compiled and run on Windows System to produce desired output as shown below :

SOURCE CODE : :

/* C Program to find frequency of vowels in String using Recursion*/


#include<stdio.h>
#include<string.h>
int count_vowels(char *str);

int main()
{
        char str[100];
        printf("Enter any string :: ");
    gets(str);
        printf("\n Total no. of vowels in String [ %s ] = %d\n",str,count_vowels(str));

        return 0;
}
int count_vowels(char *str)
{
    if(*str == '\0')
                return 0;
        switch(*str)
    {
            case 'A': case 'a':
                case 'E': case 'e':
                case 'I': case 'i':
                case 'O': case 'o':
                case 'U': case 'u':
             return 1 + count_vowels(str+1);
                default:
             return count_vowels(str+1);
    }
}

OUTPUT  : :

**************** OUTPUT **************


Enter any string :: CodezClub

 Total no. of vowels in String [ CodezClub ] = 3