how throw exception when user store string in float variable?

Question

float input;
cin>>input; // if the user type string in input then throw exception
if(!isdigit(input)){
     throw "error";
}

But isdigit also throw exception for a numeric value.

How to solve?

Answer 1

float input;
if (cin>>input) {
  //all is good
  ...
} else {
     throw "error";
}

is one way to go. Program will take if path if the input begins with a number and else path otherwise.