Numbers of vowel won't come out in the output

Question

I'm having problems with how to show the numbers of vowels in the string I input in this code I made

#include <iostream>
#include<conio.h>
using namespace std;


int main()
{
   char str[100];
   int a, e, i, o, u, whitespace;
   a = e = i = o = u = whitespace = 0;
   int k;

   cout << "Enter a string: ";
   cin >> str[99];
        
   for (k = 0; k < strlen(str); k++)
   {
       if (str[k] == 'A')
       {
           a = a + 1;
       }
       else if (str[k] == 'E')
       {
           e = e + 1;
       }
       else if (str[k] == 'I')
       {
           i = i + 1;
       }
       else if (str[k] == 'O')
       {
           o = o + 1;
       }
       else if (str[k] == 'U')
       {
           u = u + 1;
       }
       else if (str[k] == ' ')
       {
           whitespace++;
       }
   }

   cout << "\nVowels:\n";
   cout << "A " << a;
   cout << "\nE " << e;
   cout << "\nI " << i;
   cout << "\nO " << o;
   cout << "\nU " << u;
   cout << "\nWhitespaces - " << whitespace;

    return 0;
}

I hope I just need to tweak a few things because I'm new to programming lol

I typed "WELCOME TO ARRAYS" but the vowels and whitespace shows 0

The `cin >> str[99];` is wrong as it reads in only one character into the arrays last element. Try `cin >> str;`. — Adrian Mole, Jan 16 '23 at 13:45
`cin >> str[99];` reads 1 `char` and stores it in 99th position in your array; the rest of your array is uninitialized garbage. — pptaszni, Jan 16 '23 at 13:45
Consider using `std::string str;` instead of a "C" style fixed size character array. And use str.size() to get its length. — Pepijn Kramer, Jan 16 '23 at 14:02
Consider using `switch/case` statement instead of an `if-else-if` ladder. Also consider using a string search (have a string of vowels and search it). — Thomas Matthews, Jan 16 '23 at 20:09

Serve Laurijssen · Accepted Answer · 2023-01-16T13:52:39.150

2

The error is here

cin >> str[99];

You must write to the beginning of the array so just pass

cin >> str;

or if you want to be more clear pass the address of the first element

cin >> &str[0];

and str will be filled from the beginning ith the chars you enter.

The >> operator only reads until the first whitespace though, so it would only count vowels of the first word.

So in general cin.getline or std::getline is better as it reads everything

cin.getline(str,sizeof(str));

edited Jan 16 '23 at 13:52

answered Jan 16 '23 at 13:45

Serve Laurijssen

9,266
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since C++20 `operator>>` has an overload for c string (https://en.cppreference.com/w/cpp/io/basic_istream/operator_gtgt2). Then `cin >> &str[0];` is not just about readability/clarity but its less safe – 463035818_is_not_an_ai Jan 16 '23 at 13:51
(acutally I though it exists before C++20 already, but I might remember wrong and cannot find it) – 463035818_is_not_an_ai Jan 16 '23 at 13:51

Numbers of vowel won't come out in the output

1 Answers1