Second printf is not coming up and I am unsure why - c

Question

This is my code. The second printf and getchar does not pop up after hitting enter for the first scanf. I am unsure why the second printf and getchar are not working and what the fix would be.
#include <stdio.h>
int main()
{
int choice;
int i;
i = 0;
int n;
n = 1;
int p;
char message[1000];
printf("Would you like to (1) encrypt or (2) decrypt?: ");
scanf("%i\n", choice);
printf("\nType your message: ");
message[p] = getchar();
for (i = 1; (i < 1000 && message[p] != '\0');) {
message[p] = message[p] + n;
n + 1;
}
for (i = 0; (i < 1000 && message[p] != '\0');) {
message[p] = message[p] - n;
n + 1;
}
return 0;
}

Answer 1

Your encription method works for encription and decription. This compiles and takes in a string including spaces modifies it and prints it out.
#include <stdio.h>
int main() {
int choice;
char temp;
int i = 0;
int n = 1;
int p, b;
char message[1000];
char endmessage[1000];
printf("Would you like to (1) encrypt or (2) decrypt?: ");
scanf("%i", &choice); // change as per comment above
scanf("%c", &temp); /* temp statement to clear buffer otherwise a second character has to be typed before the next print statement is executed */
printf("Type your message: "); //prompt added for user clarity
scanf("%[^\n]", message); /* this scanf line allows for spaces in the message */
printf("\nmessage typed is: %s \n", message);
p = (sizeof( message) + 1); /* strings need to have an ending '\0'
message[p] = '\0';
if (choice == 1) {
for (i = 0; (i < 1000 && message[i] != '\0');) {
endmessage[i] = (message[i] + n);
i +=1;
}
b = (sizeof( endmessage)); // replace encripted \0 with '\0'
endmessage[b] = putchar('\0');
printf("\nYour message encripted is: %s\n\n", endmessage);
}
if (choice == 2) {
for (i = 0; (i < 1000 && message[i] != '\0');) {
endmessage[i] = message[i] - n;
i += 1;
}
b = (sizeof(endmessage) -2); // replace decripted \0 with '\0'
endmessage[b] = putchar('\0');
printf("\nYour message decripted is: %s\n\n", endmessage);
}
}