how do I save string without some of its characters? - c++

Question

I'm writing a programm which gives out the input string without its vowels.but it only gives the first charachter of the string .here is the code:
#include<iostream>
using namespace std;
int main(){
char ch;
while(cin.get(ch)){
cout<<ch;
char a=cin.peek();
while( a==65 || a==69 || a==73 || a==79 || a==85 || a==97 || a==101 || a==105 || a==111 || a==117)
cin.ignore(1 , a);
}
return 0;
}

Answer 1

To solve a problem like this, start by breaking the problem into smaller parts. A possible decomposition is:
Are there characters still to read from the input? No: Great, we are done!
Read in a character
Is the character a vowel? Yes: Goto 1.
Output the character
Goto 1.
Then in code, you can translate this into:
// 1) Are there characters still to read?
while (std::cin.good())
{
// 2) Read in a character
char ch;
std::cin.get(ch);
// 3) Is the character a vowel?
// For the test for a vowel, you can use something similar to
// what you have at the moment, or better still: consider
// writing a function like isVowel in #Shreevardhan answer.
if ( /* TODO: Test if the character is a vowel... */)
{
// Skip the rest of the loop and go back to 1
continue;
}
// 4) Output the good character
std::cout << ch;
// 5) Reached the end of the loop, so goto 1
}
It's a good habit to break your problem down into smaller parts. I often start a new project by first writing out a list/comments (or even drawing a flow diagram) to break up the problem into more manageable pieces.

Answer 2

Other answers show how to solve this problem in a more intuitive manner.
Anyway, when looking at your code consider the following:
while( a==65 || a==69 || a==73 || a==79 || a==85 || a==97 || a==101 || a==105 || a==111 || a==117)
cin.ignore(1 , a);
As you do a while loop with conditions around the value of a, and as cin.ignore(1 , a) does not change the value of a, you wont ever leave this loop unless an exception is thrown, right?

Answer 3

Maybe you can try to use the boost library.
#include <boost/algorithm/string.hpp>
boost::erase_all(str, "a");

Answer 4

Something like this
#include <iostream>
using namespace std;
bool isVowel(char c) {
c = tolower(c);
return c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u';
}
int main() {
char c;
while (cin.get(c))
if (!isVowel(c))
cout << c;
return 0;
}
Add your storing logic inside.
A more C++-ish code
#include <algorithm>
#include <iostream>
using namespace std;
int main() {
string s;
getline(cin, s);
s.erase(remove_if(s.begin(), s.end(), [](char c) {
c = tolower(c);
return c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u';
}), s.end());
cout << s;
return 0;
}
See a demo.