C - 行の入出力 (fopen, fgets)

プログラミング言語C 第2版 ANSI規格準拠
B.W. カーニハン D.M. リッチー (著)
石田 晴久 (翻訳)

開発環境

• OS X Lion - Apple(OS)
• Emacs、BBEdit - Bare Bones Software, Inc. (Text Editor)
• プログラミング言語: C
• Clang (コンパイラ)

プログラミング言語C 第2版 ANSI規格準拠 (B.W. カーニハン D.M. リッチー (著)、 石田 晴久 (翻訳)、共立出版)の第7章(入出力)、7.7(行の入出力)、演習7-6を解いてみる。

その他参考書籍

• プログラミング言語Cアンサー・ブック 第2版 (クロビス・L．トンド、スコット・E．ギンペル(著)、矢吹 道郎(翻訳))

演習 7-6.

コード

sample.c

#include <stdio.h>
#include <string.h>

#define MAXLINE 1000

int main(int argc, char *argv[])
{
    FILE *fp1, *fp2;
    char line1[MAXLINE], line2[MAXLINE];
    char *lp1, lp2;
    
    if (argc != 3) {
        fprintf(stderr, "コマンドライン引数に2つのファイルが指定されてない\n");
        exit(1);
    } else if ((fp1 = fopen(*++argv, "r")) == NULL) {
        fprintf(stderr, "一つ目のファイル %s を開くの失敗\n", *argv);
        exit(1);
    } else if ((fp2 = fopen(*++argv, "r")) == NULL) {
        fprintf(stderr, "二つ目のファイル %s を開くの失敗\n", *argv);
        exit(1);
    } else {
        do {
            lp1 = fgets(line1, MAXLINE, fp1);
            lp2 = fgets(line2, MAXLINE, fp2);
        } while (lp1 != NULL && lp2 != NULL && (strcmp(line1, line2) == 0));
        if (lp1 == NULL && lp2 != NULL)
            printf("line1: ファイル終了\nline2: %s", line2);
        else if (lp1 != NULL && lp2 == NULL)
            printf("line1: %sline2: ファイル終了\n", line1);
        else if (lp1 == NULL && lp2 == NULL)
            printf("違っている行は無い\n");
        else
            printf("line1 %sline2 %s", line1, line2);
    }
    return 0;
}

入出力結果(Terminal)

$ cat sample.txt
Ah Love! could you and I with Fate conspire
To grasp this sorry Scheme of Things entire,
Would not we shatter it to bits -- and then
Re-mould it nearer to the Heart's Desire!
ah love! could you and i with fate conspire
to grasp this sorry scheme of things entire,
would not we shatter it to bits -- and then
re-mould it nearer to the heart's desire!
!@#$%Ah Love! could you and I with Fate conspire
!@#$%To grasp this sorry Scheme of Things entire,
!@#$%Would not we shatter it to bits -- and then
!@#$%Re-mould it nearer to the Heart's Desire!
!@#$%ah love! could you and i with fate conspire
!@#$%to grasp this sorry scheme of things entire,
!@#$%would not we shatter it to bits -- and then
!@#$%re-mould it nearer to the heart's desire!
$ cp sample.txt sample1.txt
$ cat sample2.txt
Ah Love! could you and I with Fate conspire
To grasp this sorry Scheme of Things entire,
Would not we shatter it to bits -- and then
Re-mould it nearer to the Heart's Desire!
ah love! could you and i with fate conspire
to grasp this sorry scheme of things entire,
would not we shatter it to bits -- and then
re-mould it nearer to the heart's desire!
1234567890
!@#$%Ah Love! could you and I with Fate conspire
!@#$%To grasp this sorry Scheme of Things entire,
!@#$%Would not we shatter it to bits -- and then
!@#$%Re-mould it nearer to the Heart's Desire!
!@#$%ah love! could you and i with fate conspire
!@#$%to grasp this sorry scheme of things entire,
!@#$%would not we shatter it to bits -- and then
!@#$%re-mould it nearer to the heart's desire!
$ cat sample3.txt
Ah Love! could you and I with Fate conspire
To grasp this sorry Scheme of Things entire,
Would not we shatter it to bits -- and then
Re-mould it nearer to the Heart's Desire!
ah love! could you and i with fate conspire
to grasp this sorry scheme of things entire,
would not we shatter it to bits -- and then
re-mould it nearer to the heart's desire!
$ ./a.out sample.txt sample1.txt
違っている行は無い
$ ./a.out sample.txt sample2.txt
line1 !@#$%Ah Love! could you and I with Fate conspire
line2 1234567890
$ ./a.out sample.txt sample3.txt
line1: !@#$%Ah Love! could you and I with Fate conspire
line2: ファイル終了
$ ./a.out sample1.txt sample.txt
違っている行は無い
$ ./a.out sample2.txt sample.txt
line1 1234567890
line2 !@#$%Ah Love! could you and I with Fate conspire
$ ./a.out sample3.txt sample.txt
line1: ファイル終了
line2: !@#$%Ah Love! could you and I with Fate conspire
$