i want to getchar twice but i cant

问题

int main()
{
    int r, c;
    r = getchar();
    c = getchar();
    putchar(r);
    putchar(c);
    printf("\n");
    return(0);
}

After it reads in r, the program outputs r and quits. I want it to ask for c and input it but how come it doesnt do that?

回答1:

Are you entering the characters on the same line, or on 2 lines?

getchar() will wait until you press enter, and then start parsing the characters. If you have entered 2 characters on 2 different lines, it will read the first character and then the \n character.

What I mean is, the following input:

a
b

is equivalent to "a\nb".

getchar() will grab the \n instead of b, and print a\n\n.

You want to type both characters, and only then hit enter.

回答2:

You're probably typing X + Enter. The first getchar() reads the character X, and the second getchar() reads a newline generated when you press Enter. Type both your characters without pressing Enter.

来源：https://stackoverflow.com/questions/5609267/i-want-to-getchar-twice-but-i-cant