Using printf
Youâve already seen the print
and echo
functions, which simply
output text to the browser. But a much more powerful function, printf
, controls the format of the output by
letting you put special formatting characters in a string.
For each formatting character, printf
expects you to pass an argument that it
will display using that format. For instance, the following example uses
the %d
conversion specifier to
display the value 3 in decimal:
printf("There are %d items in your basket", 3);
If you replace the %d
with
%b
, the value 3 would be displayed in
binary (11). Table 7-1 shows
the conversion specifiers supported.
Specifier | Conversion action on argument arg | Example (for an arg of 123) |
| Display a % character (no
|
|
| Display |
|
| Display ASCII character
for the |
|
| Display |
|
| Display |
|
| Display |
|
| Display |
|
| Display |
|
| Display |
|
| Display |
|
| Display |
|
You can have as many specifiers as you like in a printf
function, as long as you pass a
matching number of arguments, and as long as each specifier is prefaced
by a %
symbol. Therefore the
following code is valid, and will output âMy name is Simon. Iâm 33 years
old, which is 21 in hexadecimalâ:
printf("My name is %s. I'm ...
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