Thread: getchar() overpasses next input

i try to use getchar to get a single character but when ever i use it it will block the very next input
using this code

Code:

#include<stdio.h>
void main (){
    char c;
    c = getchar();
    putchar(c);
    c = getchar();
    putchar(c);
    printf("End\n");
}

will take only one input, also if i replaced the second getchar() with any othe input like gets() the same problem occur.
This also happens with scanf() , so how can i prevent this from happenning.

Originally Posted by camel-man

The second getchar is picking up the newline character left in the buffer after the first getchar().

For example you enter in

- "A\n"
first getchar grabs the 'A' then the second getchar grabs the '\n' (this is from hitting the enter key)


There is a neat little trick where you can use scanf(" %c",&ch);

notice the space BEFORE the % sign. This will tell scanf to ignore any whitespace (includes newlines).

OK i know that getchar() take a second order when i press enter , so how i prevent this i don't want this to happen.
then ,notice this code

Code:

#include<stdio.h>
void main (){
    int i;
    char arr[50];
    printf("put a number\n");
    scanf("%d\n", &i);
    printf("%d\n",i);
    printf("put a txt\n");
    gets(arr);
    puts(arr);


}

it will accept digits and skips the gets() function.

Don't use "gets()"! >> FAQ > Why gets() is bad / Buffer Overflows - Cprogramming.com

The lazy option is to flush the input buffer, such as with a "while()" loop: FAQ > Flush the input buffer - Cprogramming.com

The better option is to just read an entire line at a time (fgets), and extract the information out of the resulting string (sscanf, strtol, etc).

And "main()" returns int, not void: FAQ > main() / void main() / int main() / int main(void) / int main(int argc, char *argv[]) - Cprogramming.com