Discussion on the usage of scanf () and getchar ()

First let's understand scanf and getchar Usage of .

getchar()

getchar() yes stdio.h Library functions in , Its function is to read a character from the buffer , in other words , If there is data in the buffer, you can read it directly without entering it , First call getchar() when , It really needs manual input , But if you type more than one character , After the getchar() When it is executed again, it will read directly from the buffer

And scanf Different ,getchar() Able to read spaces 、 Return, etc . and scanf When encountering space and carriage return , End reading .

commonly scanf After reading the input data , Will stay like \n Etc , And if we need to call again scanf Words , There are also \n, here scanf Don't wait for us to enter data , Just put \n Read away , So we can't achieve our goal .

therefore , In the following code to judge whether you input letters , Need to use getchar() To accept the space put into the buffer or carriage return , Otherwise ,scanf The next time you accept a space or enter , Instead of the characters you entered

That's besides using getchar() Receive spaces or carriage returns in the buffer , What else can I do ?

Another way is , stay %c Preceded by a space , It means to skip all white space characters before the next character .

meanwhile , You may have questions about the following code , Obviously, it is also a circular method of input , Why in front while You need to use getchar() To receive white space characters , And below for There is no need to write getchar Well ?

By consulting Lao Chen , I know that the original space is to distinguish between numbers ,%c Can't , in other words %c Will save spaces , but %d+ When there are spaces , Spaces are not in the cache ~.

Conclusion : This is today's sharing , Thank Lao Chen for giving me a feeling of enlightenment ~

I am cactus , Sophomores at Xiamen Software Institute , If this article helps you , Can you give me a one button three connection , Pass this article to more people who need him ~