Python Program to Print All Vowels

Extract and print all vowels from a given string, or -1 if no vowels are present.

Understand the Problem

Problem Statement

Accept a string S as the input and print all the vowels in S as the output. If there is no vowel in S then the program must print -1 as the output.

Constraints

1 <= Length of S <= 100
S can contain uppercase and lowercase letters, digits, and special characters
Vowels are defined as: a, e, i, o, u (both lowercase and uppercase)
Output must preserve the order of vowels as they appear in the input string

Examples

Example 1

Input

letuscrack

Output

eua

Explanation

The vowels in 'letuscrack' are 'e' (position 1), 'u' (position 3), and 'a' (position 7). They are printed in their original order.

Example 2

Input

Sky

Output

-1

Explanation

The string 'Sky' contains no vowels (a, e, i, o, u), so the output is -1.

Solution

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

int main() {
    char s[101];
    fgets(s, sizeof(s), stdin);
    
    // Remove newline if present
    int len = strlen(s);
    if (len > 0 && s[len-1] == '\n') {
        s[len-1] = '\0';
        len--;
    }
    
    char vowels[] = "aeiouAEIOU";
    bool found = false;
    
    for (int i = 0; i < len; i++) {
        for (int j = 0; j < 10; j++) {
            if (s[i] == vowels[j]) {
                printf("%c", s[i]);
                found = true;
                break;
            }
        }
    }
    
    if (!found) {
        printf("-1");
    }
    
    return 0;
}

Time:O(n) where n is the length of the string

Space:O(1) - only using fixed-size arrays and variables

Approach:

This C solution reads the input string using fgets(), which safely handles strings with spaces. It removes any trailing newline character. The algorithm uses two nested loops: the outer loop iterates through each character of the input string, and the inner loop checks if that character matches any vowel. When a match is found, the character is printed and we break from the inner loop. A boolean flag tracks whether any vowels were found, and if none were found, it prints -1.

Visual Explanation

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