I am working on a simple arm assembly program that gets input from the user, and calculates the area of a shape.
The program is supposed to provide an answer, wait for the user to press enter, and then display the main menu again:
The area of the rectangle is: 4
press enter to continue ...
When I run my program, it immediatly skips over my wait_for_enter subroutine, grabs whatever is still in the input buffer, and then sees that as invalid input:
The area of the rectangle is: 4
Press enter to continue...
Welcome to Area Calculation Program
Enter the shape number:
1. Triangle
2. Rectangle
3. Trapezoid
4. Square
Or enter q to quit
Invalid input. Please try again
Welcome to Area Calculation Program
Enter the shape number:
1. Triangle
2. Rectangle
3. Trapezoid
4. Square
Or enter q to quit
Currently, I am attempting to clear the buffer after I output the result:
@------------------------------------------------------------
wait_for_enter:
@ Wait for the user to hit the enter key so that the user can see the result
@ save the link register so we can return to the caller
push {lr}
@ clear the input buffer
ldr r0, =strInputPattern
ldr r1, =strInputError @ Put address into r1 for read.
bl scanf @ scan the keyboard.
@ print the prompt
ldr r0, =enterMsg
bl printf
@ read the input
ldr r0, =strInputPattern
ldr r1, =strInputError @ Put address into r1 for read.
bl scanf @ scan the keyboard.
@ return to the caller
pop {pc}
@------------------------------------------------------------
.data
.balign 4
strInputPattern: .asciz "%[^\n]" @ Used to clear the input buffer for invalid input.
.balign 4
strInputError: .skip 100*4 @ User to clear the input buffer for invalid input.
.balign 4
enterMsg: .asciz "Press enter to continue\n"
but it seems like that is not clearing everything out.
if I use %c instead of %[^\n], It seems to gobble up a lot of my input. What is the correct way to do this?
