A simple menu would be just a printed list, followed by an input command, and then some choices. Something like:
int choice = -1;
do
{
printf("Enter choice from the following:\n");
printf("0. Quit\n");
printf("1. Enter words:\n");
printf("2. Count the words:\n");
printf("3. Reverse the sentence:\n");
printf("4 ...:\n"); scanf("%d", &choice);
if (choice == 0)
break;
switch (choice)
{
case 1:
break;
default:
printf("Bad choice: %d, try again\n", choice);
break;
}
} while (1);