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sortstrings: done with no libraries

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This commit is contained in:
Claudio Maggioni 2019-10-11 09:29:40 +02:00
parent 7fb7197e75
commit 7a757657e6
2 changed files with 63 additions and 16 deletions
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49
sortstrings/sortstrings.c
View file

@ -1,30 +1,47 @@
#include <stdio.h> const unsigned int MAX_N = 1000;
#include <stdlib.h>
#include <string.h>
#define MAX_N 1000
int compar(const void* string1, const void* string2) { unsigned int c_strlen(const char* s) {
const char** s1 = (const char**) string1; unsigned int i = 0;
const char** s2 = (const char**) string2; for (; *s; s++) i++;
return strcmp(*s1, *s2); return i;
} }
void sort_strings(const char* input, const char* output, unsigned int n) { unsigned int less_than(const char *s1, const char* s2) {
for(; *s1 == *s2 && *s1; s1++) s2++;
return (*s1 < *s2);
}
void insertion_sort(const char* strs[], unsigned int n) {
for (unsigned int i = 0; i < n-1; i++) {
for (unsigned int j = i+1; j > 0; j--) {
if (less_than(strs[j], strs[j-1])) {
const char* tmp = strs[j-1];
strs[j-1] = strs[j];
strs[j] = tmp;
} else {
break;
}
}
}
}
void sort_strings(const char* input, char* output, unsigned int n) {
const char* strings[MAX_N]; const char* strings[MAX_N];
size_t i = 0; unsigned int i = 0;
size_t offset = 0; unsigned int offset = 0;
for (i = 0; i < n; i++) { for (i = 0; i < n; i++) {
strings[i] = input + offset; strings[i] = input + offset;
offset += strlen(input + offset) + 1; // + 1 for NUL offset += c_strlen(input + offset) + 1; // + 1 for NUL
} }
qsort(strings, n, sizeof(const char*), &compar); insertion_sort(strings, n);
offset = 0; offset = 0;
for (i = 0; i < n; i++) { for (i = 0; i < n; i++) {
const size_t len = strlen(strings[i]); const unsigned int len = c_strlen(strings[i]);
strncpy((char*) output + offset, (char*) strings[i], len + 1); for (unsigned int j = 0; j <= len; j++) {
output[offset + j] = strings[i][j];
}
offset += len + 1; offset += len + 1;
} }
} }

30
sortstrings/sortstrings_lib.c Normal file
View file

@ -0,0 +1,30 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_N 1000
int compar(const void* string1, const void* string2) {
const char** s1 = (const char**) string1;
const char** s2 = (const char**) string2;
return strcmp(*s1, *s2);
}
void sort_strings(const char* input, const char* output, unsigned int n) {
const char* strings[MAX_N];
size_t i = 0;
size_t offset = 0;
for (i = 0; i < n; i++) {
strings[i] = input + offset;
offset += strlen(input + offset) + 1; // + 1 for NUL
}
qsort(strings, n, sizeof(const char*), &compar);
offset = 0;
for (i = 0; i < n; i++) {
const size_t len = strlen(strings[i]);
strncpy((char*) output + offset, (char*) strings[i], len + 1);
offset += len + 1;
}
}