Question

How to shuffle array in C++

Answer 1

#include <iostream>

void swap(int arr[], int i, int j) {
    int temp = arr[i];
    arr[i] = arr[j];
    arr[j] = temp;
}
 
void shuffle(int arr[], int n) {
    for (int i = n - 1; i >= 1; i--) {
        int j = rand() % (i + 1);
        swap(arr, i, j);
    }
}

int main() {
    int arr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 };
    int len = sizeof(arr) / sizeof(arr[0]);
 
    srand(time(NULL));
 
    shuffle(arr, len);
 
    for (int i = 0; i < len; i++) {
        std::cout << arr[i] << " ";
    }

    return 0; 
}
    
    
    
      
/*
run:
    
3 4 0 1 2 7 8 9 6 5 
 
*/

 

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Answer 2

#include <iostream>
#include <algorithm>

int main() {
    int arr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11};

    std::random_shuffle(std::begin(arr), std::end(arr));

    int len = sizeof(arr) / sizeof(arr[0]);
    for (int i = 0; i < len; i++) {
        std::cout << arr[i] << " ";
    }

    return 0; 
}
    
    
    
      
/*
run:
    
5 11 8 9 1 6 3 2 7 10 4 
 
*/

 

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