MATLAB: The ‘fprintf’ problem

fprintfMATLAB

codes are as this
name = 'Alice';   age = 12;
X = sprintf('%s will be %d this year.', name, age)
y= fprintf('%d will be %d this year.', 10, 10)
why the output is as this?
where the '24' come from?
results are as this
10 will be 10 this year.
y =
    24

Best Answer

While sprintf replies the created string, the output of fprintf is the number of printed characters. In your case "10 will be 10 this year." contains 24 characters.
This is explained in the documentation, see:
doc fprintf
To be exact:
nbytes = fprintf(___) returns the number of bytes that fprintf writes,
using any of the input arguments in the preceding syntaxes.
"Bytes" mean the characters, if the output would be written to a file. Then each character uses 1 byte, althought internally the characters are stored with 2 bytes.
Rule of thumb: Whenever you have a question to a certain command, start with reading its documentation.
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