functions calling

[newguy17]

i was wondering for hours, why it always skip the input when i call the function vowels? any help would be much appreciated .

  #include<iostream>
#include<string>

void vowels();
using namespace std;

int main()
{
	int choice;
	cout<<"Enter choice: ";
	cin>>choice;
	
	if(choice==1){
		vowels();
	}
}

void vowels(){
	string str1;
	int vowels=0;
	
	cout<<"Enter strings: ";
	getline(cin,str1);
	
	for(int i=0;i<str1.length();i++)
	{
		
		if((str1[i]=='a' || (str1[i]=='e')) || (str1[i]=='i') || (str1[i]=='o') || (str1[i]=='u'))
		{
			vowels=vowels+1; //vowels++;
		}
		
	}
	
	cout<<vowels;
}

[Repeater]

https://stackoverflow.com/questions/5739937/using-getlinecin-s-after-cin

[SECMoG1T]

add any of this to line 21

std::cin.ignore(10000,'\n');

//or

std::cin.ignore(std::numeric_limits<std::streamsize>::max());

[newguy17]

thank you guys for the reply and it works. im having difficulties understanding why it needs this kind of code cin.ignore(10000,'\n')? is this common problem when calling a function with a string? thanks again.

[Repeater]

The data is read from a buffer.

The buffer contains some data, and at the end of that data is a newline character.

cin>>choice;
User enters 1 and presses ENTER, buffer looks like this:

<1> <NEWLINE>

The <1> is taken out. Buffer looks like this:

<NEWLINE>

getline(cin,str1);

getline reads from the buffer as far as <NEWLINE>. Where is the <NEWLINE>? At the front of the buffer. So getline reads nothing, and the program carries on.

cin.ignore fetches characters from the buffer and throws them away. You need to throw away that <NEWLINE> at the front of the buffer.

std::cin.ignore(10000,'\n'); means "throw away characters from the buffer until you've thrown away 10000, or until you've thrown away a NEWLINE.

std::cin.ignore(std::numeric_limits<std::streamsize>::max()); means "throw away characters from the buffer until you've thrown away some really big number of them.

[newguy17]

thank you all again and god bless.