/* strings2_copy_concat.c */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int main()
{
    char str1[12] = "Hello";  // explicit initialization
    char str2[] = "World";    // implicit initialization
    
/* Define another string variable, and allocate memory for it 'on-the-fly' */
    char * str3 = (char *) malloc ((strlen(str1)+strlen(str2)+2) * sizeof(int));
        
    printf("str1 contains \"%s\"\n",str1); // note how a double quote needs to be formatted, \"
    printf("str2 contains \"%s\"\n",str2);
    
    strcat(strcat(str1, " "), str2);  // build "Hello World" by concatenation
    strcpy(str3, str1); // copy "Hello World" to str3
    
    printf("A space and str2 concantenated to str1 is \"%s\"\n", str1);
    printf("str1 copied to str3 is \"%s\"\n", str3);
    
    free(str3); /* use malloc() in combination with free() to free memory after you have used it */
    
    return 0;
}