This question already has answers here:
C++: Why does space always terminate a string when read?
(4 answers)
Closed 2 years ago.
I wrote a code so that it removes everything(like spaces and other things) other than the alphabats using isalpha() function and converts it to lower case using tolower() function. It is working fine if i don't put a space in the string but if there is any space in the string then it go beyond the space. I dont understand why this is happening. This is the code i wrote.
#include<bits/stdc++.h>
#include<cstring>
#include<cctype>
using namespace std;
int main()
{
int i;
string A,b="";
cin>>A;
for(i=0;i<A.size();i++)
{
if(isalpha(A[i]))
b+= tolower(A[i]);
else
continue;
}
cout<<b;
}
Please help me.
Thankyou
The cin >> A; considers the space to terminate the input.
To get the whole line, use getline(cin, A);
cin reads the string till the first space it encounters, if your input string is "Hello World", then cin will only read "Hello".
You can use getline function to read a complete line.
Related
This question already has answers here:
Using getline(cin, s) after cin [duplicate]
(13 answers)
Why does std::getline() skip input after a formatted extraction?
(5 answers)
Closed 6 years ago.
#include<iostream>
#include<cstring>
using namespace std;
int main() {
int t;
cin >> t;
string s;
getline(cin, s);
cout << s;
return 0;
}
As soon as I press the enter key after giving input for t, the program terminates as string takes the newline character as input. What can I do? I cannot output something between these two inputs and an enter after t is mandatory.
The Enter key you press to end the input for t is added to the input buffer. So the first input in the buffer seen by getline is the Enter key and it thinks you have given an empty line.
Use the ignore function to skip past the newline:
std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
You can also use two std::getline calls, and use e.g. std::stoi to convert the input an int. Or put in an std::istringstream and extract using the normal >> operator.
You may use getline(cin, s) twice. Fist will ignore rest of first line and the second will actually read what you need or better use cin.ignore() with appropriate arguments
This question already has answers here:
std::getline on std::cin
(3 answers)
Closed 7 years ago.
I want to write a program which reads in a line and a character and then print them together iterally. This is my code:
#include <string>
#include <iostream>
using namespace std;
int main() {
string s;
string a;
while (getline(cin,s)) {
cin>>a;
cout<<s<<a<<endl;
}
}
The first time I input:"abc d" as a line and then "a" as a character and
the output is "abc da".
But then I input "abc d" again, it immediately output "abc" without waiting for me to input "a" and then output "abc da". Where is my code wrong?
After the cin>>a; there is still a newline in the buffer which is then read by the getline(). To avoid this you need to flush the newline out of the buffer. This can be achieved by calling cin.ignore() and in some cases cin.sync(), although I am not sure of the exact functionality of the cin.sync() function.
This question already has answers here:
Using getline(cin, s) after cin [duplicate]
(13 answers)
Closed 7 years ago.
#include <iostream>
using namespace std;
int main(int argc, char** argv) {
char text[200];
int input;
cin>>input;
if (input == 1)
{
cin.getline(text, 200);
cout<<text<<"\n";
}
else if(input == 0)
{
cout <<"You entered a 0";
}
return 0;
}
I am trying to make a small program where the user gives an input either a 1 or 0. if the user enters a 1 then he can enter a whole sentence and stores it in the char array of text. My problem is that when I put the cin.getline() inside an if statement it no longer works. why is that?
Thanks
It is not that cin.getline() doesn't work. It does exactly what has been asked of it: Read the line of text up to the next newline. It just so happens that cin >> input; has read some digits and then left the first non-digit input in the input buffer - which typically is a newline unless you typed something that wasn't a number.
You can work around this by calling cin.ignore(), which will "read everything up to the next newline and throw it away".
Ideally, you should decide whether you want to use cin >> or cin.getline(), and use one or the other, but that means then reading a string of text and in your code converting to a digit, and if you are a novice, that's probably a bit more complex than you actually want to make it.
This question already has answers here:
cin and getline skipping input [duplicate]
(4 answers)
Closed 8 years ago.
i have a problem with input char to my program
#include <iostream>
using namespace std;
int main()
{
int choise;
char word[81];
cin >> choise;
cout << "enter the word:" << endl;
cin.getline(word, 81);
return 0;
}
the visual studio open the input to "choise"
but skip on cin.getline (it the same if i replace it with gets_s).
i tried to write
cin.get(); before the "getline"...
but then the program not get's the first char
(if i put 'aa' it get 'a')
what can i do?
thanks
Its because you entered a newline for the program to accept the integer you entered for choice, the that newline is not extracted from the buffer, leaving it to be read in your next input operation. The getline call reads that left-over newline, and is happy with that.
There are a couple of ways to solve your problem. The first and most obvious is to use std::string for the word variable, and then use the normal input operator >> as that will skip leading whitespace (which includes newline).
Another solution is to tell the input stream to ignore until and including a newline. The linked reference has an example on how to do exactly that.
After entering the integer you press enter, and this enter input is left in the buffer area and used as the next input for getline and the computer assumes you're done.
add this line before getline statement and re- compile it.
cin.ignore().
This question already has answers here:
std::cin.getline( ) vs. std::cin
(5 answers)
Closed 8 years ago.
#include<iostream.h>
#include<conio.h>
class String
{
char str[100];
public:
void input()
{
cout<<"Enter string :";
cin>>str;
}
void display()
{
cout<<str;
}
};
int main()
{
String s;
s.input();
s.display();
return 0;
}
I am working in Turbo C++ 4.5. The code is running fine but its not giving the desired output
for e.g if i give input as "steve hawking" only "steve" is being displayed. Can anyone please help?
Using >> on a stream reads one word at a time. To read a whole line into a char array:
cin.getline(str, sizeof str);
Of course, once you've learnt how to implement a string, you should use std::string and read it as
getline(cin, str);
It would also be a very good idea to get a compiler from this century; yours is over 15 years old, and C++ has changed significantly since then. Visual Studio Express is a good choice if you want a free compiler for Windows; other compilers are available.
cin>>str;
This only reads in the next token. In C++ iostreams, tokens are separated by whitespace, so you get the first word.
You probably want getline, which reads an entire line into a string:
getline(cin, str);
You can use :
cin.read( str, sizeof(str) );
But, this will fill up the buffer. Instead you should use cin.getLine() as MikeSeymour suggested
You could use cin.getline to read the whole line.
use this
cin.getline(cin, str);