quicksort.c

qs.c

#include<stdlib.h>
#include<stdio.h>
#include<time.h>

int partition(int* a, int p, int r) {
    int x = a[p];
    int i = p;
    for(int j = p + 1; j < r; j++) {
        if(a[j] <= x) {
            i++;
            int temp = a[i];
            a[i] = a[j];
            a[j] = temp;
        }
    }
    int temp = a[i];
    a[i] = a[p];
    a[p] = temp;
    return i;
}

void quick_sort(int* a, int p, int r) {
    if(p < r) {
        int q = partition(a, p, r);
        quick_sort(a, p, q - 1);
        quick_sort(a, q + 1, r);
    }
}


int main() {
    char filename[1000];
    printf("Enter file name:\n");
    scanf("%s", filename);
    FILE* file = fopen(filename, "rw");
    int length;
    fscanf(file, " %d", &length);\
    printf("Length of array %d\n", length);

    int* array1 = (int*) malloc(sizeof(int) * (length));
    for(int i = 0; i < length; i++) {
        fscanf(file, " %d", &array1[i]);
    }
   
    
    clock_t start_time, end_time;
    double quicksort_time_taken_ms;
   
    printf("Quick Sort Trial:\n");
    start_time = clock();
    quick_sort(array1, 0, length);
    end_time = clock();
    quicksort_time_taken_ms = ((double)(end_time - start_time)) / CLOCKS_PER_SEC * 1000.0;
    printf("Time Taken for Quick Sort: %f milliseconds.\n", quicksort_time_taken_ms);
    printf("\n");
    // printf("Results of Quick Sort:\n");
    // for(int i = 0; i < length; i++) {
    //     printf("%d ", array1[i]);
    // }
    // printf("\n");
    return 0;
}