/*
 * adder.c - a minimal CGI program that adds two numbers together
 */
/* $begin adder */
#include "csapp.h"

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

    /* Extract the two arguments */
    if ((buf = getenv("QUERY_STRING")) != NULL) {
      if (sscanf(buf, "n1=%d&n2=%d\n", &n1, &n2) == 2) 
	sprintf(msg, "%d + %d -> %d\n", n1, n2, n1+n2);
      else
	sprintf(msg, "Can't parse buffer '%s'\n", buf);
    }
    /* Make the response body */
    sprintf(content, "Welcome to add.com: ");
    sprintf(content, "%sTHE Internet addition portal.\r\n<p>", content);
    sprintf(content, "%sThe answer is: %s\r\n<p>", 
	    content, msg);
    sprintf(content, "%sThanks for visiting!\r\n", content);
  
    /* Generate the HTTP response */
    printf("Content-length: %u\r\n", (unsigned) strlen(content));
    printf("Content-type: text/html\r\n\r\n");
    printf("%s", content);
    fflush(stdout);
    exit(0);
}
/* $end adder */