String_Question_1

################################## DOES NOT WORK ######################################################
#
#   Output:
# gcc -Wall -Wextra -std=c11 crap.c -o crap.o
# crap.c: In function ‘main’:
# crap.c:10:7: warning: ‘firstName’ is used uninitialized in this function [-Wuninitialized]
#   scanf("%s", firstName);
#        ^
# crap.c:12:7: warning: ‘lastName’ is used uninitialized in this function [-Wuninitialized]
#   scanf("%s", lastName);
#        ^
#######################################################################################################

#include <stdio.h>

int main(void)
{

        char * firstName;
        char * lastName;

        printf("What is your first name?\n");
        scanf("%s", firstName);
        printf("What is your last name?\n");
        scanf("%s", lastName);

        printf("Your full name is %s %s\n", firstName, lastName);

        return(0);
}

####################### WORKS #####################################
#include <stdio.h>

int main(void)
{

        char firstName[20];
        char lastName[20];

        printf("What is your first name?\n");
        scanf("%s", firstName);
        printf("What is your last name?\n");
        scanf("%s", lastName);

        printf("Your full name is %s %s\n", firstName, lastName);

        return(0);
}

###################### THIS ALSO WORKS ###############################
#include <stdio.h>
#include <stdlib.h>

int main(void)
{
        char * firstName;
        char * lastName;
        /*
        * Curretly, firstName and lastName do not have any space
        * reserved in memory. Therefore we cannot save any variables to
        * the location they point to.
        */

        // Allocate 20 bytes. Don't forget to free.
        firstName = (char *) malloc(20);
        lastName = (char *) malloc(20);

        printf("What is your first name?\n");
        scanf("%s", firstName);
        printf("What is your last name?\n");
        scanf("%s", lastName);

        printf("Your full name is %s %s\n", firstName, lastName);

        free(firstName);
        free(lastName);
        return(0);
}