2019-03-31 11:00:21 +00:00
---
title: '『[新版C言語プログラミングレッスン 入門編』 第四章 if'
author: kazu634
date: 2008-03-23
wordtwit_post_info:
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categories:
- C
- Programming
---
< div class = "section" >
< p >
つづきだよー
< / p >
< p >
< a name = "seemore" > < / a >
< / p >
< h4 >
論理和「||」
< / h4 >
< pre class = "syntax-highlight" >
< span class = "synPreProc" > #include < / span > < span class = "synConstant" > < stdio.h> < / span >
< span class = "synPreProc" > #include < / span > < span class = "synConstant" > < stdlib.h> < / span >
< span class = "synPreProc" > #define MAX_LINE < / span > < span class = "synConstant" > 128< / span > < span class = "synPreProc" > < / span > < span class = "synComment" > /* 入力行の最大長 */< / span >
< span class = "synType" > int< / span > main(< span class = "synType" > void< / span > );
< span class = "synType" > int< / span > main(< span class = "synType" > void< / span > )
{
< span class = "synType" > char< / span > buf[MAX_LINE];
< span class = "synType" > int< / span > n;
printf (< span class = "synConstant" > " 降水確率を入力してください。</ span >< span class = "synSpecial" > \n</ span >< span class = "synConstant" > " </ span > );
gets(buf);
n = atoi(buf);
printf (< span class = "synConstant" > " 降水確率は </ span >< span class = "synSpecial" > %d</ span >< span class = "synConstant" > </ span >< span class = "synSpecial" > %%</ span >< span class = "synConstant" > です。</ span >< span class = "synSpecial" > \n</ span >< span class = "synConstant" > " </ span > , n);
< span class = "synStatement" > if< / span > (n < < span class = "synConstant" > < / span > || < span class = "synConstant" > 100< / span > < n) {
printf (< span class = "synConstant" > " 降水確率は0 - 100の間ですよ。</ span >< span class = "synSpecial" > \n</ span >< span class = "synConstant" > " </ span > );
}
< span class = "synStatement" > else< / span > < span class = "synStatement" > if< / span > (n > = < span class = "synConstant" > 50< / span > ) {
printf (< span class = "synConstant" > " 傘を忘れずにね。</ span >< span class = "synSpecial" > \n</ span >< span class = "synConstant" > " </ span > );
}
< span class = "synStatement" > else< / span > {
printf (< span class = "synConstant" > " 傘はいりません。</ span >< span class = "synSpecial" > \n</ span >< span class = "synConstant" > " </ span > );
}
printf (< span class = "synConstant" > " いってらっしゃい</ span >< span class = "synSpecial" > \n</ span >< span class = "synConstant" > " </ span > );
< span class = "synStatement" > return< / span > (< span class = "synConstant" > < / span > );
}
< / pre >
< p >
or は「||」で表現する。
< / p >
< h4 >
現在の時間を入力してもらって、それに応じたメッセージを表示させる
< / h4 >
< pre class = "syntax-highlight" >
< span class = "synPreProc" > #include < / span > < span class = "synConstant" > < stdio.h> < / span >
< span class = "synPreProc" > #include < / span > < span class = "synConstant" > < stdlib.h> < / span >
< span class = "synPreProc" > #define MAX_LINE < / span > < span class = "synConstant" > 128< / span > < span class = "synPreProc" > < / span > < span class = "synComment" > /* 入力行の最大長 */< / span >
< span class = "synType" > int< / span > main(< span class = "synType" > void< / span > );
< span class = "synType" > int< / span > main(< span class = "synType" > void< / span > )
{
< span class = "synType" > char< / span > buf[MAX_LINE];
< span class = "synType" > int< / span > n;
printf (< span class = "synConstant" > " 現在の時刻（「時」だけでよい）を教えてください。</ span >< span class = "synSpecial" > \n</ span >< span class = "synConstant" > " </ span > );
gets(buf);
n = atoi(buf);
< span class = "synStatement" > if< / span > (n < < span class = "synConstant" > < / span > || < span class = "synConstant" > 24< / span > < n) {
printf (< span class = "synConstant" > " Hour must be:</ span >< span class = "synSpecial" > \n</ span >< span class = "synConstant" > 0 < = hour < = 24</ span >< span class = "synSpecial" > \n</ span >< span class = "synConstant" > " </ span > );
}
< span class = "synStatement" > else< / span > < span class = "synStatement" > if< / span > (< span class = "synConstant" > < / span > < = n & & n < = < span class = "synConstant" > 11< / span > ) {
printf (< span class = "synConstant" > " おはようございます。</ span >< span class = "synSpecial" > \n</ span >< span class = "synConstant" > " </ span > );
}
< span class = "synStatement" > else< / span > < span class = "synStatement" > if< / span > (n == < span class = "synConstant" > 12< / span > ) {
printf (< span class = "synConstant" > " お昼です。</ span >< span class = "synSpecial" > \n</ span >< span class = "synConstant" > " </ span > );
}
< span class = "synStatement" > else< / span > < span class = "synStatement" > if< / span > (< span class = "synConstant" > 13< / span > < = n & & n < = < span class = "synConstant" > 18< / span > ) {
printf (< span class = "synConstant" > " こんにちわ。</ span >< span class = "synSpecial" > \n</ span >< span class = "synConstant" > " </ span > );
}
< span class = "synStatement" > else< / span > < span class = "synStatement" > if< / span > (< span class = "synConstant" > 19< / span > < = n & & n < = < span class = "synConstant" > 23< / span > ) {
printf (< span class = "synConstant" > " こんばんわ。</ span >< span class = "synSpecial" > \n</ span >< span class = "synConstant" > " </ span > );
}
< span class = "synStatement" > return< / span > (< span class = "synConstant" > < / span > );
}
< / pre >
< p >
境界にあたる場合の条件に注意。自分の場合、「=」をつけ忘れていた。
< / p >
< h4 >
ここまでで Perl と違うと思った部分
< / h4 >
< ul >
< li >
必ず main から始まる
< / li >
< li >
変数の方を最初に宣言しなければならない
< / li >
< li >
Perl だとコンテクストに応じて様々な姿を変数はとるけれど、 C だと自分で型を変換しなければならない（→ atoi ）
< / li >
< li >
C の char 型は一文字しか格納できない。だから配列として宣言して文字列を格納している…ようだ
< / li >
< / ul >
< p >
自分は Perl のコンテクストみたいな考えの方が好きかもしれない。
< / p >
2019-04-02 16:06:15 +00:00
< / div >
