Array non repeated alphabets, C (gcc)

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//gcc 4.9.3

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

void input(int *p,int n)
{
    int i;
    srand(getpid());
    for(i=0;i<n;i++)
    {
        p[i]=rand()%26+65;
       if(ifRepeated(p,i))
        {
             i--;
        }
    }
                   
}

void print(int *p,int n)
{
    int i;
    printf("**the array***\n");
    for(i=0;i<n;i++)
        printf("p[%d]=%c\n",i,p[i]);
}
void vowles(int *p,int n)
{
    int i,ch;
    printf("***VOWLES***\n");
    for(i=0;i<n;i++)
    {
        switch(p[i])
        {
            case 'A':printf("p[%d]=%c\n",i,p[i]);
                       break;
            case 'E':printf("p[%d]=%c\n",i,p[i]);
                       break;
            case 'I':printf("p[%d]=%c\n",i,p[i]);
                       break;
            case 'O':printf("p[%d]=%c\n",i,p[i]);
                       break;
            case 'U':printf("p[%d]=%c\n",i,p[i]);
                       break;
        }
            
    }
}

int ifRepeated(int *p,int i)
{
    int j=i-1;
    while(j>=0)
    {
        if(p[j]==p[i])
            return 1;
        j--;
    }
    return 0;
}

main()
{
    int a[20];
    int n;
    n=sizeof(a)/sizeof(a[0]);
    input(a,n);
    print(a,n);
    vowles(a,n);
     
}

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Compilation time: 0.12 sec, absolute running time: 0.14 sec, cpu time: 0 sec, memory peak: 3 Mb, absolute service time: 0,34 sec