61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
#include <stdio.h>
|
|
#include <math.h>
|
|
|
|
int is_prime(int);
|
|
|
|
int populate_array(int * array, size_t size) {
|
|
int index = 0;
|
|
for (int i = 1; i < size; i++) {
|
|
if ( is_prime(i) ) {
|
|
array[index++] = i;
|
|
}
|
|
}
|
|
return index;
|
|
}
|
|
|
|
int is_present(int * array, size_t size, int number);
|
|
|
|
void parr(int * array, size_t size, size_t numbers) {
|
|
for (int i = 1; i < numbers; i++)
|
|
printf("%d IS PRESENT: %d\n",i, is_present(array, size, i));
|
|
}
|
|
|
|
int is_prime(int number) {
|
|
for (int i = 2; i <= number/2; i++) {
|
|
if ( number % i == 0 ) {
|
|
return 0;
|
|
}
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
int _is_present(int * array, int number, int low, int high) {
|
|
int middle = ((high + low) / 2.0);
|
|
//printf("L: %d H: %d M: %d N: %d\n", low, high, middle, number);
|
|
if ( number > array[middle] ) {
|
|
return _is_present(array, number, middle, high);
|
|
} else if ( number < array[middle] ) {
|
|
return _is_present(array, number, low, middle);
|
|
} else if ( number == array[middle] ) {
|
|
return 1;
|
|
} else {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
int is_present(int * array, size_t size, int number) {
|
|
if ( is_prime(number) ) {
|
|
return _is_present(array, number, 0, size);
|
|
} else {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
int main(void) {
|
|
int primes[100];
|
|
int real_primes = populate_array(primes, 100);
|
|
//parr(primes, real_primes, 100);
|
|
printf("%d\n", is_present(primes, real_primes, 6));
|
|
printf("%d\n", is_present(primes, real_primes, 13));
|
|
return 0;
|
|
}
|