Is there a way to test if an input is a number in C++?

Question

Question's all in the title. I'm making a calculator and I obviously need input. I use the cin>> function but I was wondering if there is a way to test the input to find out if it's a number. If I enter anything that isn't a number the program crashes. Is there a built in function/operator? Please help!

Answer 1

The input operator will only read to an integer if the input is a number. Otherwise it will leave the characters in the input buffer.

Try something like this

int i;
if (cin >> i)
{
    // input was a number
}
else
{
    // input failed
}

Answer 2

atoi和sscanf是你的朋友，或者只是比较输入的charcode是否在“0” - “9”范围内