How to write a script for the following?

1 x 8 + 1 = 9
12 x 8 + 2 = 98
123 x 8 + 3 = 987
1234 x 8 + 4 = 9876
12345 x 8 + 5 = 98765
123456 x 8 + 6 = 987654
1234567 x 8 + 7 = 9876543
12345678 x 8 + 8 = 98765432
123456789 x 8 + 9 = 987654321

The script should iterate from 1 to 9 to produce the expressions on the left, then perform the specified operation to get the results on the right, and finally print exactly in the format above

Thank you!

Answer 1

[Stephen23]

>> for k=1:9, n=sscanf(sprintf('%d',1:k),'%d'); fprintf('%d x 8 + %d = %d\n',n,k,n*8+k); end
1 x 8 + 1 = 9
12 x 8 + 2 = 98
123 x 8 + 3 = 987
1234 x 8 + 4 = 9876
12345 x 8 + 5 = 98765
123456 x 8 + 6 = 987654
1234567 x 8 + 7 = 9876543
12345678 x 8 + 8 = 98765432
123456789 x 8 + 9 = 987654321
>>

[Zhuoying Lin]

Thank you! Yet I haven't learned sscanf

[Stephen23]

You can learn about sscanf by reading the MATLAB documentation:

https://www.mathworks.com/help/matlab/ref/sscanf.html

Alternatively you can simply replace sscanf with str2double:

>> for k=1:9, n=str2double(sprintf('%d',1:k)); fprintf('%d x 8 + %d = %d\n',n,k,n*8+k); end
1 x 8 + 1 = 9
12 x 8 + 2 = 98
123 x 8 + 3 = 987
1234 x 8 + 4 = 9876
12345 x 8 + 5 = 98765
123456 x 8 + 6 = 987654
1234567 x 8 + 7 = 9876543
12345678 x 8 + 8 = 98765432
123456789 x 8 + 9 = 987654321

Remember to accept the answer that best resolves your question!

[Zhuoying Lin]

Is there any other way to do it if I don't use or sscanf or str2double?

[Stephen23]

@Zhuoying Lin: of course, there are always other ways of doing things. You could calculate n without any strings at all, which might even be more efficient:

n = sum((k:-1:1).*10.^(0:k-1));

e.g.

>> for k=1:9, n=sum((k:-1:1).*10.^(0:k-1)); fprintf('%d x 8 + %d = %d\n',n,k,n*8+k); end
1 x 8 + 1 = 9
12 x 8 + 2 = 98
123 x 8 + 3 = 987
1234 x 8 + 4 = 9876
12345 x 8 + 5 = 98765
123456 x 8 + 6 = 987654
1234567 x 8 + 7 = 9876543
12345678 x 8 + 8 = 98765432
123456789 x 8 + 9 = 987654321

[Zhuoying Lin]

Okay!Thank you very much!

Answer 2

[Walter Roberson]

for loop and use fprintf()

[Zhuoying Lin]

Yes I know what it is tested on but I have no idea how to compose it