さまざまな文字列操作

明解Ｃ言語入門編 > 11. 文字列とポインタ >

C



#include <stdio.h>

#include <string.h>
int main(int argc, char* argv[])

{

    /* strcat */

    char st1[100] = "1234567890";

    char st2[100] = "ABCDE";
    printf("%s + ", st1);

    printf("%s = ", st2);

    strcat(st1, st2);

    printf("%s\n", st1);
    char st3[100] = "1234567890";

    printf("%s + ", st3);

    printf("%s = ", st2);

    strncat(st3, st2, 4);

    printf("%s\n", st3);
    char st4[100] = "1234567890";

    printf("%s + ", st4);

    printf("%s = ", st2);

    strncat(st4, st2, 6);

    printf("%s\n", st4);

    puts("");
    /* strrev */

    printf("%s\n", st4);

    printf("%s\n", strrev(st4));

    puts("");
    /* strcmp */

    char* pt1 = "123";

    char* pt2 = "123";
    int i = strcmp(pt1, pt2);

    if (i == 0)

        printf("%s = %s (%d)\n", pt1, pt2, i);

    else if (i > 0)

        printf("%s > %s (%d)\n", pt1, pt2, i);

    else

        printf("%s < %s (%d)\n", pt1, pt2, i);
    pt2 = "122";

    i = strcmp(pt1, pt2);

    if (i == 0)

        printf("%s = %s (%d)\n", pt1, pt2, i);

    else if (i > 0)

        printf("%s > %s (%d)\n", pt1, pt2, i);

    else

        printf("%s < %s (%d)\n", pt1, pt2, i);
    pt2 = "124";

    i = strcmp(pt1, pt2);

    if (i == 0)

        printf("%s = %s (%d)\n", pt1, pt2, i);

    else if (i > 0)

        printf("%s > %s (%d)\n", pt1, pt2, i);

    else

        printf("%s < %s (%d)\n", pt1, pt2, i);
    pt2 = "999";

    i = strcmp(pt1, pt2);

    if (i == 0)

        printf("%s = %s (%d)\n", pt1, pt2, i);

    else if (i > 0)

        printf("%s > %s (%d)\n", pt1, pt2, i);

    else

        printf("%s < %s (%d)\n", pt1, pt2, i);
    pt2 = "12";

    i = strcmp(pt1, pt2);

    if (i == 0)

        printf("%s = %s (%d)\n", pt1, pt2, i);

    else if (i > 0)

        printf("%s > %s (%d)\n", pt1, pt2, i);

    else

        printf("%s < %s (%d)\n", pt1, pt2, i);
    pt2 = "1234";

    i = strcmp(pt1, pt2);

    if (i == 0)

        printf("%s = %s (%d)\n", pt1, pt2, i);

    else if (i > 0)

        printf("%s > %s (%d)\n", pt1, pt2, i);

    else

        printf("%s < %s (%d)\n", pt1, pt2, i);
    puts("");
    /* stricmp */

    pt1 = "ABCD";

    pt2 = "abcd";

    i = strcmp(pt1, pt2);

    if (i == 0)

        printf("%s = %s (%d)\n", pt1, pt2, i);

    else if (i > 0)

        printf("%s > %s (%d)\n", pt1, pt2, i);

    else

        printf("%s < %s (%d)\n", pt1, pt2, i);
    i = stricmp(pt1, pt2);

    if (i == 0)

        printf("%s = %s (%d)\n", pt1, pt2, i);

    else if (i > 0)

        printf("%s > %s (%d)\n", pt1, pt2, i);

    else

        printf("%s < %s (%d)\n", pt1, pt2, i);
    puts("");
    /* strstr */

    pt1 = "1234567890";

    pt2 = "45";

    char* pt3 = strstr(pt1, pt2);

    printf("strstr(\"%s\", \"%s\") = %u\n", pt1, pt2, pt3 - pt1);
    pt2 = "12";

    pt3 = strstr(pt1, pt2);

    printf("strstr(\"%s\", \"%s\") = %u\n", pt1, pt2, pt3 - pt1);
    pt2 = "123456780";

    pt3 = strstr(pt1, pt2);

    if (pt3 != '\0')

        printf("strstr(\"%s\", \"%s\") = %u\n", pt1, pt2, pt3 - pt1);

    else

        printf("strstr(\"%s\", \"%s\") = NULL\n", pt1, pt2);
    puts("");
    /* strchr */

    pt1 = "1294567890";

    char c = '9';

    pt3 = strchr(pt1, c);

    printf("strchr(\"%s\", \"%c\") = %u\n", pt1, c, pt3 - pt1);
    c = 'A';

    pt3 = strchr(pt1, c);

    if (pt3 != '\0')

        printf("strchr(\"%s\", \"%c\") = %u\n", pt1, c, pt3 - pt1);

    else

        printf("strchr(\"%s\", \"%c\") = NULL\n", pt1, c);
    puts("");
    /* strrchr */

    c = '9';

    pt3 = strrchr(pt1, c);

    printf("strrchr(\"%s\", \"%c\") = %u\n", pt1, c, pt3 - pt1);
    c = 'A';

    pt3 = strrchr(pt1, c);

    if (pt3 != '\0')

        printf("strrchr(\"%s\", \"%c\") = %u\n", pt1, c, pt3 - pt1);

    else

        printf("strrchr(\"%s\", \"%c\") = NULL\n", pt1, c);
    puts("");

    pt1 = "1234567890";
    /* strpbrk */

    pt2 = "ABCD8";

    pt3 = strpbrk(pt1, pt2);

    if (pt3 != '\0')

        printf("strpbrk(\"%s\", \"%s\") = %u\n", pt1, pt2, pt3 - pt1);

    else

        printf("strpbrk(\"%s\", \"%s\") = NULL\n", pt1, pt2);
    pt2 = "ABCDE";

    pt3 = strpbrk(pt1, pt2);

    if (pt3 != '\0')

        printf("strpbrk(\"%s\", \"%s\") = %u\n", pt1, pt2, pt3 - pt1);

    else

        printf("strpbrk(\"%s\", \"%s\") = NULL\n", pt1, pt2);
    puts("");
    /* strcspn */

    pt2 = "0";

    i = strcspn(pt1, pt2);

    printf("strcspn(\"%s\", \"%s\") = %u\n", pt1, pt2, i);
    pt2 = "A";

    i = strcspn(pt1, pt2);

    printf("strcspn(\"%s\", \"%s\") = %u\n", pt1, pt2, i);
    puts("");
    /* strtok */

    pt1 = "a\\bcd\\efg";

    pt2 = "\\";

    printf("pt1 = %s\n", pt1);
    pt3 = strtok(pt1, pt2);

    printf("pt1 = %s, pt3 = %s\n", pt1, pt3);
    pt3 = strtok('\0', pt2);

    printf("pt1 = %s, pt3 = %s\n", pt1, pt3);
    pt3 = strtok('\0', pt2);

    printf("pt1 = %s, pt3 = %s\n", pt1, pt3);
    return 0;

}

実行結果



T:\>lesson087\project1.exe

1234567890 + ABCDE = 1234567890ABCDE

1234567890 + ABCDE = 1234567890ABCD

1234567890 + ABCDE = 1234567890ABCDE
1234567890ABCDE

EDCBA0987654321
123 = 123 (0)

123 > 122 (1)

123 < 124 (-1)

123 < 999 (-8)

123 > 12 (51)

123 < 1234 (-52)
ABCD < abcd (-32)

ABCD = abcd (0)
strstr("1234567890", "45") = 3

strstr("1234567890", "12") = 0

strstr("1234567890", "123456780") = NULL
strchr("1294567890", "9") = 2

strchr("1294567890", "A") = NULL
strrchr("1294567890", "9") = 8

strrchr("1294567890", "A") = NULL
strpbrk("1234567890", "ABCD8") = 7

strpbrk("1234567890", "ABCDE") = NULL
strcspn("1234567890", "0") = 9

strcspn("1234567890", "A") = 10
pt1 = a\bcd\efg

pt1 = a, pt3 = a

pt1 = a, pt3 = bcd

pt1 = a, pt3 = efg