Using Sprintf on matlab

Part b) Display the content of “log10(A)” on the screen using “sprintf” in the following format: “A is [1 10 100 1000]. log10(A) calculated using the natural logarithm function is [0 1 2 3].” In the format above, where the numbers are bold, the values of “A” and “log10(A)” must be used instead of simply typing the numbers. In other words, do not simply type in the entire line above between two quotation marks of “sprint”, but use a format similar to the following: sprint(‘A is [ %? ]. log10(A) calculated using the natural logarithm function is [ %?]’ ,A,?) What you need to find is the format to display “A” and “log10(A)”, e.g. %u, %d, %s etc (the first and second question marks) and the function you defined in part (a) for the third question mark.

Answer 1

[Star Strider]

See the documentation for sprintf.

[Matthew Liao]

so your saying I have to type sprint(‘A is [ 1 10 100 1000 ]. log10(A) calculated using the natural logarithm function is [0 1 2 3]’ ,A,?).

but when I type this is giving me an error saying

Error: Unbalanced or unexpected parenthesis or bracket.

[Image Analyst]

No, he said to look up the documentation for sprintf so you know that the four numbers get replaced by %f (four of them) and the variables themselves are listed after the format string

message = sprintf('A is [%f %f.............', A, ......);

See if you can fill in the missing parts for your homework. I can't just do the whole homework outright for you of course.

[Star Strider]

Please show your actual code. The function is sprintf, so ‘sprint’ will throw an error. You will need to use the necessary format descriptors (such as %f) to output your numbers.

For example:

Q = [3:5];
sprintf('Q = [%.1f %.1f %.1f]', Q)

produces:

Q = [3.0 4.0 5.0]

[Matthew Liao]

logarithmic = sprintf('A is [%f %f %f %f], log10(A) calculated using the natural logarithm function is [%u %u %u %u]',A,C)

which works but when I did it this way it gave me some weird numbers

logarithmic = sprintf('A is [%u %u %u %u]',A,'log10(A) calculated using the natural logarithm function is [%u %u %u %u]',C)

logarithmic =

A is [1 10 100 1000]A is [108 111 103 49]A is [48 40 65 41]A is [32 99 97 108]A is [99 117 108 97]A is [116 101 100 32]A is [117 115 105 110]A is [103 32 116 104]A is [101 32 110 97]A is [116 117 114

[Star Strider]

I would use ‘%f’ for the natural logarithm function output as well. The ‘%u’ is for base 10 unsigned integers, and will produce strange results.

This works perfectly for me:

A = [1 10 100 1000];
C = log(A);
logarithmic = sprintf('A is [%f %f %f %f], log10(A) calculated using the natural logarithm function is [%f %f %f %f]',A,C)

and produces:

logarithmic =

A is [1.000000 10.000000 100.000000 1000.000000], log10(A) calculated using the natural logarithm function is [0.000000 2.302585 4.605170 6.907755]