THIS IS LANGUAGE 'C' NOT C++

The Problem is, even though I use two 'scaf' to input two different character, as you can see in the picture, one of the two 'scanf' that scans character gets skipped; as a result, the code executes --> "floating exception (core dumped)"

But for my homework, I have to input two different characters (just one letter (it could be capital and it could be lower case ) and the task is to play around with ASCII Table with the two input characters; and I have no clue why this is giving me such an error. PLEASE HELP ME~!!

But I want the output to be

size of bit ---> Input Letter --> b or B

int main() char a_prefix; char b or B; double byteCalculation; double bitsCalculation; int size b; char unit; int numPrefix; printf(" size of bite >"); scanf("%d",&size b printf("Input Letter (G T M) -> "); scanf ("%c", &a-prefix) ; printf ("b or B ") scanf ("%c", &unit) ; size of bite --> 3 Input Letter (G T M) --> b or B two separate "scan