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>> DAVID MALAN: Suppose we'd like to write
a program that prompts the user

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for a string and then capitalizes
that string.

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Well, let's start with some familiar
code declaring a string called s and

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assigning it the return
value of getstring.

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And let's now proceed to iterate over
the characters in this string.

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Well, how to do that?

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It turns out that a string is just a
sequence of characters, but more

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properly, a string is an array of
characters, which means we can use

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square bracket notation to index into
a string and get at individual

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characters.

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>> In other words, we can
do the following.

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For int, i gets 0, and n gets,
say, the length of s, using

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our function [? stir ?]

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[? line, ?]

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i is less than n i++.

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In other words, with this loop, we
will iterate over all n letters

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in the string s.

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And within this loop, I'm going to
check, if the i-th character in s

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greater than or equal to lowercase a,
and the i-th character is less than or

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equal to a lowercase c, then I want to
proceed to capitalize that letter.

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In other words, I want to print out %c
as a placeholder and substitute in for

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that placeholder s bracket i.

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>> But then I need to convert
s bracket i to uppercase.

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To do this, I can simply subtract
whatever the difference is between

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lowercase a and capital A. Well, I
actually do recall that capital A is

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65 in ASCII, and lowercase a is 97.

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So the difference is technically 32.

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So I could just hard code 32 here.

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But I might not necessarily
remember those numbers.

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>> And moreover, what if they
vary by computer?

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Most likely they're not.

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But the point remains that I can still
generalize that arithmetic expression

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as just whatever the difference is
between a lowercase a and a capital A

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is what I want to subtract off from
this particular lowercase letter.

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>> Now, if this particular letter
is not lowercase, I simply

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want to print it out.

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printf, %c as my placeholder,
s bracket i.

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At the bottom of this program, let's
simply print out newline so that my

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prompt appears on a new
line of its own.

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>> Let's now compile this program
with make capitalize0.

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Let's run it with capitalize0.

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And let's type in a word like
hello in all lowercase.

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I get back HELLO in uppercase
as expected.

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But let's try one more test, this time
with my own name, D-A-V-I-D, but with

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the first D capitalized, just in
case I messed something up

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with that first char.

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Enter, and D-A-V-I-D in uppercase
is printed as well.

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