diff options
| -rw-r--r-- | 05/main.c | 20 | ||||
| -rw-r--r-- | 05/string.h | 67 |
2 files changed, 72 insertions, 15 deletions
@@ -3,7 +3,7 @@ #include <stdio.h> #include <signal.h> #include <stdlib.h> - +#include <string.h> int compar(const void *a, const void *b) { int i = *(int *)a; @@ -14,20 +14,10 @@ int compar(const void *a, const void *b) { } int main(int argc, char **argv) { - ldiv_t l = ldiv(1000000000007, 5937448); - printf("%ld %ld\n",l.quot,l.rem); - int nums[10] = {8,34,1086,3872,-123,5873,3843,1762,INT_MAX,INT_MIN}; - int i; - for (i = 0; i < 10; ++i) nums[i] = abs(nums[i]); - qsort(nums, 10, sizeof(int), compar); - for (i = 0; i < 10; ++i) printf("%d ", nums[i]); - printf("\n"); - int search = 34; - int *p = bsearch(&search, nums, 10, sizeof(int), compar); - if (p) - printf("Found %d\n",*p); - else - printf("No match\n"); + char buf[36]; + memset(buf, 'a', sizeof buf); + strncpy(buf, "hello, world!\n",36); + printf("%d\n",strcmp(buf, "hello, world!\n")); return 0; } diff --git a/05/string.h b/05/string.h index e585f6b..9b59637 100644 --- a/05/string.h +++ b/05/string.h @@ -4,5 +4,72 @@ #include <stdc_common.h> +void *memmove(void *s1, const void *s2, size_t n) { + if (s1 < s2) return memcpy(s1, s2, n); // our memcpy does a forwards copy + // backwards copy + char *p = (char*)s1 + n, *q = (char*)s2 + n; + while (p > s1) + *--p = *--q; + return s1; +} + +char *strcpy(char *s1, const char *s2) { + char *p = s1 - 1, *q = s2 - 1; + while ((*++p = *++q)); + return s1; +} + +char *strncpy(char *s1, const char *s2, size_t n) { + char *p = s1 - 1, *q = s2 - 1; + size_t i; + for (i = 0; i < n; ++i) + if (!(*++p = *++q)) + break; + for (; i < n; ++i) + *++p = 0; + return s1; +} + +char *strcat(char *s1, const char *s2) { + return strcpy(s1 + strlen(s1), s2); +} + +char *strncat(char *s1, const char *s2, size_t n) { + // oddly, not equivalent to strncpy(s1 + strlen(s1), s2, n) + char *p = s1 + strlen(s1) - 1, *q = s2 - 1; + size_t i; + for (i = 0; i < n; ++i) + if (!(*++p = *++q)) + break; + *++p = 0; + return s1; +} + +int memcmp(const void *s1, const void *s2, size_t n) { + char *p = s1, *q = s2; + size_t i; + for (i = 0; i < n; ++i, ++p, ++q) { + if (*p > *q) + return 1; + if (*p < *q) + return -1; + } + return 0; +} + +int strcmp(const char *s1, const char *s2) { + char *p = s1, *q = s2; + for (; *p && *q; ++p, ++q) { + if (*p > *q) + return 1; + if (*p < *q) + return -1; + } + if (*p > *q) + return 1; + if (*p < *q) + return -1; + return 0; +} #endif // _STRING_H |