1-19.c

演習 1-19 文字列sを逆に並べる関数reverse(s)を書け。さらに、この関数を使って、入力を一時に１行ずつ逆転するプログラムを書け。

#include <stdio.h>
#define MAXLINE 1000

void reverse(char s[])
{
        int c, len;
        char temp;

        for (len = 0; s[len] != '\0'; ++len)
                ;
        --len;

        for (c = 0; c < len; ++c, --len) {
                temp = s[c];
                s[c] = s[len];
                s[len] = temp;
        }
}

main()
{
        int c;
        int i = 0;
        char line[MAXLINE];
        while ((c = getchar()) != EOF) {
                if (c == '\n') {
                        line[i] = '\0';
                        reverse(line);
                        printf("%s\n", line);
                        i = 0;
                } else {
                        line[i++] = c;
                }
        }
        return 0;
}

$ /a.out < 1-19.c

>h.oidts< edulcni#

0001 ENILXAM enifed#
)][s rahc(esrever diov

{

;nel ,c tni

;pmet rahc
)nel++ ;'0\' =! ]nel[s ;0 = nel( rof

;

;nel--
{ )nel-- ,c++ ;nel < c ;0 = c( rof

;]c[s = pmet

;]nel[s = ]c[s

;pmet = ]nel[s

}

}
)(niam

{

;c tni

;0 = i tni

;]ENILXAM[enil rahc

{ )FOE =! ))(rahcteg = c(( elihw

{ )'n\' == c( fi

;'0\' = ]i[enil

;)enil(esrever

;)enil ,"n\s%"(ftnirp

;0 = i

{ esle }

;c = ]++i[enil

}

}

;0 nruter

}