/*
 * adder.c - a minimal CGI program that adds two numbers together
 *
 * Jim: 
 *   - changed content-type: to text/plain
 *   - put in some debugging comments
 *
 * command line test : 
 *     $ QUERY_STRING="2&3" ./adder
 *     Connection: close
 *     Content-length: 99
 *     Content-type: text/plain
 *
 *     Welcome to add.com: THE Internet addition portal.
 *     The answer is: 2 + 3 = 5
 *     Thanks for visiting!
 */

/* $begin adder */
#include "csapp.h"

int main(void) {
    char *buf, *p;
    char arg1[MAXLINE], arg2[MAXLINE], content[MAXLINE];
    int n1=0, n2=0;

    /* Extract the two arguments */
    if ((buf = getenv("QUERY_STRING")) != NULL) {

        //printf("getenv(QUERY_STRING) = '%s'\n", buf);
      
	p = strchr(buf, '&');
	*p = '\0';
	strcpy(arg1, buf);
	strcpy(arg2, p+1);

	//printf("arg1 string : '%s'\n", buf);
	//printf("arg2 string : '%s'\n", p+1);
	
	n1 = atoi(arg1);
	//printf("n1 = %d\n", n1);
	n2 = atoi(arg2);
	//printf("n2 = %d\n", n2);
    }

    /* Make the response body */
    sprintf(content, "Welcome to add.com: ");
    sprintf(content, "%sTHE Internet addition portal.\r\n", content);
    sprintf(content, "%sThe answer is: %d + %d = %d\r\n", 
	    content, n1, n2, n1 + n2);
    sprintf(content, "%sThanks for visiting!\r\n", content);
  
    /* Generate the HTTP response */
    printf("Connection: close\r\n");
    printf("Content-length: %d\r\n", (int)strlen(content));
    printf("Content-type: text/plain\r\n\r\n");
    printf("%s", content);
    fflush(stdout);

    exit(0);
}
/* $end adder */