Thread: segfaulting!

Im getting a segmentation fault when I try to run the program and add new message. As soon as I input the 3 values it segfaults. Any help?

Code:

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

struct MSG {
	int priority;
	int destination;
	char *message;
	int length;
	struct MSG *nextPtr;
};

typedef struct MSG Message;

int main ()
{
	struct MSG {
		int priority;
		int destination;
		char *message;
		int length;
		struct MSG *nextPtr;
	};

	struct MSG std[100];
	int I;
	int n;
	
	
	
	int choice = 0;


do
{
	printf("1.) Quit\n");
	printf("2.) Transmit next message\n");
	printf("3.) List messages by priority\n");
	printf("4.) Summarize message list\n");
	printf("5.) Add new message\n");
	printf(":");
	scanf("%d", &choice);
	switch(choice)
	{
		case 1:
			return 0;
		case 2:
			//transmit next message
			break;
		case 3:
			//list messages by priority
			break;
		case 4:
			//summarize message list
			break;
		case 5:
			//add new message
		        printf("How many messages would you like to enter?\n");
			scanf("%d", &n);
			printf("Enter a priority, destination, and message:");
			for (I=0; I < n; I++)
			{
				scanf("%d%d%s", &std[I].priority, &std[I].destination, &std[I].message);
			}
			printf("\ntest info:");
			for (I=0; I < n; I++)
			{
				printf("%d%d%s\n", std[I].priority, std[I].destination, std[I].message);
			}
			break;
		default:
			printf("Invalid entry, please try again.\n");
			break;
	}
}while (choice <= 5);

	return 0;
}