1
00:00:00,000 --> 00:00:00,366

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>> SPEAKER: We'll call it a string.

3
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It's just a sequence of characters.

4
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Indeed, it's simply an
array of characters.

5
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And so even if we get a string from the
user in the usual way with CS50's

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GetString, we can then proceed to
iterate over the chars in that string

7
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one at a time as though that
string is indeed an array.

8
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Let's try this in code.

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>> Include cs50.h.

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Include stdio.h.

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And let's also include string.h
so that we have access

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to StringLen function.

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Let's now declare main
as int main void.

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And let's now proceed to get
a string from the user.

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Printf input.

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Let's now declare a string calling it
s, and call our friend GetString.

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>> Let's now proceed to check, did the user
indeed give me a string because

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it turns out per GetString's own
documentation, GetString could on

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occasion return NULL, a special sentinel
value that essentially

20
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indicates that the user did not
cooperate and somehow did

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not provide a string.

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So let's check for that
with a condition.

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>> IF s does not equal NULL, then we can
assume that s is indeed a string, an

24
00:01:09,300 --> 00:01:14,580
array of characters, and proceed to
iterate over those characters.

25
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FOR int i gets 0, let's also declare n
as equal to the string length of s so

26
00:01:22,240 --> 00:01:27,900
long as i is less than n, and on each
iteration, let's increment i.

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Within this loop THEN, let's call printf
of %c backslash n and then plug

28
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into this value s bracket i thereby
printing one character at a time each

29
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of the cars in s.

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>> Let's now compile and
run this program.

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Make string.

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./string My input will be "hello."
And there we have it.

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H-E-L-L-O, each char on its own line.

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