googletest gives either multiple main defination when libgtest_main.a is used or gives undefined reference to testing when libgtest_main.a is not used [duplicate]

I built googletest following the steps given in this link ->

https://www.eriksmistad.no/getting-started-with-google-test-on-ubuntu/

Here is my code

  1 #include <iostream>
  2 #include <vector>
  3 #include "gtest.h"
  4 //#include <gtest.h>
  5
  6 using namespace std;
  7
  8 void expectEqual(int n1, int n2){
  9         if(n1 != n2){
 10          cerr << "Actual value is " << n1 << ", expected " << n2 <<endl;
 11         }
 12 }
 13
 14 int binarySearch(vector <int> &arr, int key){
 15
 16 int low = 0;
 17 int high = arr.size() -1 ;
 18 while(low <= high){
 19         int mid = (low + high) / 2;
 20         if(arr[mid] == key){
 21                 return mid;
 22         } else if (arr[mid] < key){
 23                 low = mid + 1;
 24         }
 25         else {
 26                 high = mid - 1;
 27         }
 28
 29         }
 58
 59 TEST(BinarySearchTest, EmptyVectorTest) {
 60         vector<int> arr;
 61         arr.push_back(5);
 62         expectEqual(binarySearch(arr, 10), -1);
 63 }
 64
 65
 66 /*int main() {
 67
 68         basicTest();
 69         smallVectorTest();
 70         emptyVectorTest();
 71         return 0;
 72 }*/
 73
 74 int main(int argc, char **argv){
 75         ::testing::InitGoogleTest(&argc, argv);
 76         return RUN_ALL_TESTS();
 77 }
 78

This is how I compile it using a bash script ->

  1 #!/bin/bash
  2
  3 INC_DIR=/usr/include/gtest/
  4 LIB_DIR=/usr/lib/
  5
  6 #g++ -std=c++11 -isystem $INC_DIR -pthread -L$LIB_DIR -lgtest -lgtest_main binarySearch.cpp 
    #gives multiple definition of `main'; error

  7 #g++ -std=c++11 -isystem $INC_DIR -pthread $LIB_DIR/libgtest.a binarySearch.cpp
   #gives undefined reference to `testing::InitGoogleTest(int*, char**)'

  8 g++ -std=c++11 -isystem $INC_DIR -pthread $LIB_DIR/libgtest_main.a binarySearch.cpp
   #gives multiple definition of `main'; error

For reference, I am also pasting how LIB and Include path looks -->

storm@storm:~/cpp_ut$ ls /usr/lib/
X11                gnupg
accountsservice    gnupg2
apparmor           gold-ld
apt                groff
bfd-plugins        hdparm
binfmt.d           init
bolt               initcpio
byobu              initramfs-tools
cloud-init         kernel
cnf-update-db      klibc
command-not-found  klibc-xcgdUApi-P9SoPhW_fi5gXfvWpw.so
compat-ld          language-selector
console-setup      libDeployPkg.so.0
cpp                libDeployPkg.so.0.0.0
cryptsetup         libdmmp.so
dbus-1.0           libdmmp.so.0.2.0
dpkg               libgtest.a
dracut             libgtest_main.a

storm@storm:~/cpp_ut$ ls /usr/include/gtest/
gtest-death-test.h  gtest-message.h     gtest-printers.h  gtest-test-part.h   gtest.h            gtest_prod.h
gtest-matchers.h    gtest-param-test.h  gtest-spi.h       gtest-typed-test.h  gtest_pred_impl.h  internal

Every answer that I found on StackOverflow for a similar issue suggests I use either libgtest.a or libgtest_main.a. Both does not resolve my issue.

I apologize for the long question, but I wanted to include all the possible information.