使用汇编语言 从键盘输入一个长度不超过30的字符串，其中包含自己的班级名称+学号+姓名的拼音（班级和姓名的首字母大写），以“$”符号结束，之后完成以下任务（要求使用子程序）： 屏幕显示输出该字符串； 将该字符串的奇数位置字符提取出来，组合成一个字符串显示输出。 将该字符串中的所有数字字符剔除，然后显示输出； 将该字符串中的英文大写字母变成小写字母，小写字母变成大写字母，显示输出； 统计该字符串中的大写字母、小写字母和数字的个数，保存在内存变量中，并在屏幕上显示； 将该字符串中的数字进行累加，将累加结果显示输出。

以下是使用汇编语言实现以上任务的代码：

.model small
.stack 100h

.data
msg db 0ah, 0dh, 'Please enter a string (no more than 30 characters, end with "$"): $'
str db 31 dup('$')
odd db 15 dup('$')
no_digit db 31 dup('$')
count_upper dw 0
count_lower dw 0
count_digit dw 0
sum dw 0
result db 0ah, 0dh, 'Output:', 0ah, 0dh, '$'
result_odd db 0ah, 0dh, 'Odd characters:', 0ah, 0dh, '$'
result_no_digit db 0ah, 0dh, 'No digit characters:', 0ah, 0dh, '$'
result_count db 0ah, 0dh, 'Count:', 0ah, 0dh, 'Upper:', 0ah, 0dh, 'Lower:', 0ah, 0dh, 'Digit:', 0ah, 0dh, '$'
result_sum db 0ah, 0dh, 'Sum:', 0ah, 0dh, '$'

.code
main proc
    mov ax, @data
    mov ds, ax

    ; prompt user to enter a string
    mov ah, 09h
    lea dx, msg
    int 21h

    ; read string from keyboard
    lea si, str
    mov cx, 31
    mov ah, 01h
read_loop:
    int 21h
    cmp al, '$'
    je input_done
    mov [si], al
    inc si
    loop read_loop
input_done:
    mov [si], '$'

    ; display original string
    lea dx, result
    mov ah, 09h
    int 21h
    lea dx, str
    mov ah, 09h
    int 21h

    ; extract odd characters
    lea si, str
    lea di, odd
    mov cx, 0
    extract_loop:
    mov al, [si]
    cmp al, '$'
    je extract_done
    inc cx
    cmp cx, 2
    jne skip_odd
    mov [di], al
    inc di
    skip_odd:
    inc si
    loop extract_loop
extract_done:
    mov [di], '$'

    ; display odd characters
    lea dx, result_odd
    mov ah, 09h
    int 21h
    lea dx, odd
    mov ah, 09h
    int 21h

    ; remove digit characters
    lea si, str
    lea di, no_digit
    remove_digit_loop:
    mov al, [si]
    cmp al, '$'
    je remove_digit_done
    cmp al, '0'
    jb not_digit
    cmp al, '9'
    ja not_digit
    jmp next_char
    not_digit:
    mov [di], al
    inc di
    next_char:
    inc si
    loop remove_digit_loop
remove_digit_done:
    mov [di], '$'

    ; display string without digits
    lea dx, result_no_digit
    mov ah, 09h
    int 21h
    lea dx, no_digit
    mov ah, 09h
    int 21h

    ; change case of letters
    lea si, str
    change_case_loop:
    mov al, [si]
    cmp al, '$'
    je change_case_done
    cmp al, 'A'
    jb next_char2
    cmp al, 'Z'
    ja next_char2
    add al, 20h
    jmp next_char2
    next_char2:
    cmp al, 'a'
    jb next_char3
    cmp al, 'z'
    ja next_char3
    sub al, 20h
    jmp next_char3
    next_char3:
    mov [si], al
    inc si
    loop change_case_loop
change_case_done:

    ; count upper, lower, and digit characters
    lea si, str
    count_loop:
    mov al, [si]
    cmp al, '$'
    je count_done
    cmp al, 'A'
    jb next_char4
    cmp al, 'Z'
    ja next_char4
    inc count_upper
    jmp next_char4
    next_char4:
    cmp al, 'a'
    jb next_char5
    cmp al, 'z'
    ja next_char5
    inc count_lower
    jmp next_char5
    next_char5:
    cmp al, '0'
    jb next_char6
    cmp al, '9'
    ja next_char6
    inc count_digit
    add ah, al
    adc dh, 0
    next_char6:
    inc si
    loop count_loop
count_done:

    ; display count results
    lea dx, result_count
    mov ah, 09h
    int 21h
    mov ax, count_upper
    call print_word
    mov ax, count_lower
    call print_word
    mov ax, count_digit
    call print_word

    ; display sum of digits
    lea dx, result_sum
    mov ah, 09h
    int 21h
    mov ax, sum
    call print_word

    mov ah, 4ch
    int 21h
main endp

; print a word in decimal format
print_word proc value:word
    push ax
    push bx
    push dx

    mov ax, value
    mov bx, 10
    xor cx, cx

    print_digit_loop:
    xor dx, dx
    div bx
    push dx
    inc cx
    cmp ax, 0
    jne print_digit_loop

    print_loop:
    pop dx
    add dl, '0'
    mov ah, 02h
    int 21h
    loop print_loop

    pop dx
    pop bx
    pop ax
    ret
print_word endp

end main