CODEWITHSUNDEEP
cloopsgetchar
carlitos_30
carlitos_30

Reputation: 31

Counting number of user input using getchar() gives double the expected result, why?

In the following example, from the book "C programming", when input characters, the program count twice.

main(){

long nc;

nc = 0;
while (getchar() != EOF)
    ++nc;
    printf("%ld\n", nc);
}

OUTPUT:

a
b
c
d
e
f
12

What's wrong?

I'am using Ubuntu and the gcc compiler.

Upvotes: 2

Views: 487

Answers (1)

Sourav Ghosh
Sourav Ghosh

Reputation: 134326

It's counting properly. getchar() is considering the ENTER key press also, as a newline \n. So 6 user inputs and 6 newlines. Counts match.

If you don't want the newlines to be counted as inputs, you need to increment the counter when the getchar() return value is not \n, something like

while ( (c = getchar()) != EOF) {
    if  ( c != '\n')  ++nc;
    }

will get the job done. Note, c should be of type int to be able to handle EOF.

That said, as per C99 or C11, for a hosted environment, the signature of main() should at least be int main(void) to conform to the standard.

Upvotes: 6

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