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

int main()
{

    int a[10], i,t;
    for (i = 0; i<10; i++)
        a[i] = rand()%10;

    for (i = 0; i<10; i++)
        printf("%d ",a[i]);
    printf("\n");
    for (i = 0; i+1<10; i+=2)
    {
        t = a[i];
        a[i] = a[i+1];
        a[i+1] = t;
    }
    for (i = 0; i<10; i++)
        printf("%d ",a[i]);
}