Caesar Cipher

main.c

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

void cipher(char* p);
int main()
{
    char input[100];
    printf("Input Your string: ");
    fgets(input,100,stdin);
    cipher(&input);
    printf("Encypted String is: ");
    puts(input);
    return 0;
}

void cipher(char* p)
{
    int i;
    char input[100];
    i=0;
    while(p[i]!='\0')
    {
        if (p[i]==' ')
        {
            i++;
            continue;
        }
        p[i]=p[i]+3;
        i++;
    }
    p[i]='\0';
}