Question

How to print the N smallest numbers in array with C

Answer 1

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

int compare_function(const void* a, const void* b) {
    return (*(int*)a - *(int*)b);
}

void printNSmallest(int arr[], int size, int N) {
    qsort(arr, size, sizeof(int), compare_function);

    for (int i = 0; i < N; i++)
        printf("%3d", arr[i]);
}

int main(void) {
    int arr[] = { 50, 99, 20, 100, 76, 33, 87, 40, 81, 80 };
    int size = sizeof(arr) / sizeof(arr[0]);
    int N = 4;

    printNSmallest(arr, size, N);

    return 0;
}




/*
run:

 20 33 40 50

*/

 

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Answer 2

#include <stdio.h>

int getMin(int arr[], int size) {
    int min = arr[0];
    for (int i = 1; i < size; i++) {
        if (arr[i] < min)
            min = arr[i];
    }

    return min;
}

int getSecondSmalles(int arr[], int size, int min) {
    int second_smallest = arr[0];

    for (int i = 1; i < size; i++) {
        if (arr[i] < second_smallest && arr[i] > min)
            second_smallest = arr[i];
    }

    return second_smallest;
}

void printNSmallest(int arr[], int size, int N) {
    int min = getMin(arr, size);
    int second_smallest = min;
    printf("%3d", min);

    for (int i = 1; i < N; i++) {
        second_smallest = getSecondSmalles(arr, size, second_smallest);
        printf("%3d", second_smallest);
    }
}

int main(void) {
    int arr[] = { 50, 99, 20, 100, 76, 33, 87, 40, 81, 80 };
    int size = sizeof(arr) / sizeof(arr[0]);
    int N = 4;

    printNSmallest(arr, size, N);

    return 0;
}




/*
run:

 20 33 40 50

*/

 

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