I have a very basic question i want to take integer input in certain range from user. if the user gives some string or char instead of integer. then my program goes to infinite loop.
my code is some what like that
cin >> intInput;
while(intInput > 4 || intInput < 1 ){
cout << "WrongInput "<< endl;
cin >> intInput;
}
I am only allowed to use c++ libraries not the c libraries.
As mentioned in the possible duplicate, you should check the state of cin on each loop.
Possible implementation:
if(cin >> intInput)
while(intInput > 4 || intInput < 1 ){
cout << "WrongInput "<< endl;
if(!(cin >> intInput)){ break; }
}
Very ugly code, just trying to illuminate the answer which is to check the state of cin.
The solution to this answer is to always read lines from the standard input.
std::string input; int value = 0;
do
{
// read the user's input. they typed a line, read a line.
if ( !std::getline(std::cin,input) )
{
// could not read input, handle error!
}
// attemp conversion of input to integer.
std::istringstream parser(input);
if ( !(parser >> value) )
{
// input wasn't an integer, it's OK, we'll keep looping!
}
}
// start over
while ((value > 4) || (value < 1));
#include <locale>
..
if(!isalpha(intInput)) {
..
}
Note, this won't work if, for example the user enters a "+" but maybe it will put you in the right direction..
intInput is obviously an integer, so you can't use isalpha on it