I try to do interpolation search with the data from the struct. For example I give as input the time 2014-02-13T18:50:00 and I want interpolation search return the temp 4.0 and the hum 75 but something doesn't work. I think the problem appears when calculate mid with (High-Low)*(In-Low) but I don't understand why this happen.
#include <stdio.h>
#include <stdlib.h>
#define SIZE 11
struct metrhseis{
char time[21];
int temp;
int hum;
};
long long int string_To_long(const char arr[]);
void interpolation_search(struct metrhseis arr[], char * in);
int main(){
char in[25];
int inI;
int j;
struct metrhseis s[SIZE];
strcpy(s[0].time, "2014-02-13T06:20:00");
s[0].temp=3.0;
s[0].hum=93;
strcpy(s[1].time, "2014-02-13T13:50:00");
s[1].temp=7.0;
s[1].hum=66;
strcpy(s[2].time, "2014-02-13T06:00:00");
s[2].temp=2;
s[2].hum=91;
strcpy(s[3].time, "2014-02-13T03:00:00");
s[3].temp=3;
s[3].hum=84;
strcpy(s[4].time, "2014-02-13T13:00:00");
s[4].temp=6;
s[4].hum=62;
strcpy(s[5].time, "2014-02-13T18:50:00");
s[5].temp=4.0;
s[5].hum=75;
strcpy(s[6].time, "2014-02-13T13:20:00");
s[6].temp=6.0;
s[6].hum=70;
strcpy(s[7].time, "2014-02-13T15:00:00");
s[7].temp=6;
s[7].hum=56;
strcpy(s[8].time, "2014-02-13T08:50:00");
s[8].temp=4.0;
s[8].hum=87;
strcpy(s[9].time, "2014-02-13T21:50:00");
s[9].temp=4.0;
s[9].hum=75;
strcpy(s[10].time, "2014-02-13T08:00:00");
s[10].temp=3;
s[10].hum=88;
int i;
for (i = 0; i < SIZE; i++)
printf("%s\n%d\n%d\n", s[i].time, s[i].temp,s[i].hum);
printf("Date:");
scanf("%s",in);
interpolation_search(s, in);
}
void interpolation_search(struct metrhseis arr[], char * in){
long long int High,Low,In;
long long int mid,low,high;
low=0;
high =SIZE - 1 ;
High = string_To_long(arr[high].time);
Low = string_To_long(arr[low].time);
In = string_To_long(in);
while(low<=high ){
High= string_To_long(arr[high].time);
Low= string_To_long(arr[low].time);
mid =low+(high-low)/(High-Low)*(In-Low);
if(strcmp(arr[mid].time,in)>0){
high=mid-1;
}
else if(strcmp(arr[mid].time,in)<0){
low=mid+1;
}
else
printf("Time: %s Temperatura: %d Hum: %d",arr[mid].time ,arr[mid].temp,arr[mid].hum);
break;
}
printf("Time: %s Temperatura: %d Hum: %d", in,arr[mid].temp,arr[mid].hum);
}
long long string_To_long(const char arr[]) {
long long int n = 0;
for (int i = 0; arr[i] != '\0'; i++) {
char c = arr[i];
if (c >= '0' && c <= '9')
n = n * 10 + (c - '0');
}
return n;
}
Use an ordered list Then compute ratio between two time and finally display temp and hum
For 2014-02-13T13:40:00 get
Time: 20140213134000 Temperatura: 6.666667 Hum: 67.333336
#include <stdio.h>
#include <stdlib.h>
struct metrhseis{
long long int time;
int temp;
int hum;
struct metrhseis *next;
};
long long int string_To_long(const char arr[]);
void interpolation_search(struct metrhseis *list, const char * in);
void add_metrhseis(struct metrhseis **list, const char *time, int temp, int hum);
void list_delete(struct metrhseis **list);
void list_print(struct metrhseis *list);
int main(){
char in[25];
struct metrhseis *list = NULL;
add_metrhseis(&list, "2014-02-13T06:20:00", 3.0, 93);
add_metrhseis(&list, "2014-02-13T13:50:00", 7.0, 66);
add_metrhseis(&list, "2014-02-13T06:00:00", 2, 91);
add_metrhseis(&list, "2014-02-13T03:00:00", 3, 84);
add_metrhseis(&list, "2014-02-13T13:00:00", 6, 62);
add_metrhseis(&list, "2014-02-13T18:50:00", 4.0, 75);
add_metrhseis(&list, "2014-02-13T13:20:00", 6.0, 70);
add_metrhseis(&list, "2014-02-13T15:00:00", 6, 56);
add_metrhseis(&list, "2014-02-13T08:50:00", 4.0, 87);
add_metrhseis(&list, "2014-02-13T21:50:00", 4.0, 75);
add_metrhseis(&list, "2014-02-13T08:00:00", 3, 88);
list_print(list);
printf("Date:");
scanf("%s",in);
interpolation_search(list, in);
list_delete(&list);
}
void list_print(struct metrhseis *m) {
printf("List\n");
do {
printf("%lld:%d,%d\n", m->time, m->temp, m->hum);
m = m->next;
} while (m);
}
void list_delete(struct metrhseis **list) {
struct metrhseis *m = *list;
if (m->next) {
list_delete(&m->next);
}
free(m);
*list = NULL;
}
void add_metrhseis(struct metrhseis **list, const char *time, int temp, int hum)
{
struct metrhseis *current = *list;
struct metrhseis *m = malloc(sizeof(struct metrhseis));
m->time = string_To_long(time);
m->temp = temp;
m->hum = hum;
if (*list == NULL || (*list)->time > m->time) {
m->next = *list;
*list = m;
return;
}
while (current->next && current->next->time <= m->time) {
current = current->next;
}
m->next = current->next;
current->next = m;
}
void interpolation_search(struct metrhseis *list, const char * in) {
long long int time = string_To_long(in);
float ratio;
if (time < list->time) {
printf("Time: %s Temperatura: %d Hum: %d\n", in, list->temp, list->hum);
return;
}
while(list->next && list->next->time < time) {
list = list->next;
}
if (!list->next) {
printf("Time: %s Temperatura: %d Hum: %d\n", in, list->temp, list->hum);
return;
}
ratio = (float)(time - list->time) / (list->next->time - list->time);
printf("Time: %s Temperatura: %f Hum: %f\n",
in,
list->temp + ratio * (list->next->temp - list->temp),
list->hum + ratio * (list->next->hum - list->hum )
);
return;
}
long long string_To_long(const char arr[]) {
long long int n = 0;
for (int i = 0; arr[i] != '\0'; i++) {
char c = arr[i];
if (c >= '0' && c <= '9')
n = n * 10 + (c - '0');
}
return n;
}