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Question

http://www.stanford.edu/class/cs106b/assignments/Assignment1-linux.zip

I am self-studying this assignment for an upcoming Coursera course. I modified Warmup.cpp in 0-Warmup folder as following:

#include <iostream>
#include <string>
#include "StanfordCPPLib/console.h"
using namespace std;

/* Constants */

const int HASH_SEED = 5381;               /* Starting point for first cycle */
const int HASH_MULTIPLIER = 33;           /* Multiplier for each cycle      */
const int HASH_MASK = unsigned(-1) >> 1;  /* All 1 bits except the sign     */

/* Function prototypes */

int hashCode(string key);

/* Main program to test the hash function */

int main() {
   string name;
   cout << "Please enter your name: "; 
   getline(cin, name); 
   int code = hashCode(name);
   cout << "The hash code for your name is " << code << "." << endl;
   return 0;
}
int hashCode(string str) {
   unsigned hash = HASH_SEED;
   int nchars = str.length();
   for (int i = 0; i < nchars; i++) {
      hash = HASH_MULTIPLIER * hash + str[i];
   }
   return (hash & HASH_MASK);
}

It gives me this error:

andre@ubuntu-Andre:~/Working/Assignment1-linux/0-Warmup$ g++ Warmup.cpp -o a
/tmp/ccawOOKW.o: In function `main':
Warmup.cpp:(.text+0xb): undefined reference to `_mainFlags'
Warmup.cpp:(.text+0x21): undefined reference to `startupMain(int, char**)'
collect2: ld returned 1 exit status

What is wrong here?

---

UPDATE: Got this to work now.

1. cd to the folder containing assignment.cpp
2. g++ assignment.cpp StanfordCPPLib/*.cpp -o a -lpthread

StanfordCPPLib/*.cpp this part indicate that everything in the library will be compiled,
-pthread will link pthread.h, which is used by several utilities in the Stanford library.

Answer 1

A random "StanfordCPPLib/console.h" I found on the net includes fun code like:

#if CONSOLE_FLAG | GRAPHICS_FLAG

#define main main(int argc, char **argv) { \
extern int _mainFlags; \
_mainFlags = GRAPHICS_FLAG + CONSOLE_FLAG; \
return startupMain(argc, argv); \
} \
int Main

extern int startupMain(int argc, char **argv);

So your main() function is apparently really a function called Main() that is ultimately called by some support function, startupMain() , that's in a library your instructor should provide.

You need to link to that library. Your assignment or course notes should have instructions on how to do that and where the library comes from.