title: ‘cout’ is not a member of ‘std’ & ‘cout’ was not declared in this scope
body: <p>I realize that there are several duplicates like this but none of them have worked for me so far. 
  I am trying to compile a C++ very simple program on Ubuntu using g++ but it is giving me scope errors.</p>
  
  <pre><code>#include &lt;iostream&gt;
  using namespace std;
  
  int main()
  {
    cout &lt;&lt; "Hello world";
  }
  </code></pre>
  
  <p><strong>This gives me this error:</strong></p>
  
  <pre><code>sudo g++ -v test.c
  test.c: In function ‘int main()’:
  test.c:7:3: error: ‘cout’ was not declared in this scope
  </code></pre>
  
  <p>I also tried defining the scope as many other posts say, but that also didn't work, but gave me a different error:</p>
  
  <pre><code>#include &lt;iostream&gt;
  
  int main()
  {
    std::cout &lt;&lt; "Hello world";
  }
  </code></pre>
  
  <p><strong>Gives error:</strong></p>
  
  <pre><code>test.c: In function ‘int main()’:
  test.c:6:3: error: ‘cout’ is not a member of ‘std’
  </code></pre>
  
  <p>Most of the suggestions online suggest "using namespace std;", "#include " and "std::cout". 
  So I tried all 3 together, still no luck :(</p>
  
  <pre><code>#include &lt;iostream&gt;
  using namespace std;
  
  int main()
  {
    std::cout &lt;&lt; "Hello world";
  }
  </code></pre>
  
  <p><strong>gives error:</strong></p>
  
  <pre><code>test.c: In function ‘int main()’:
  test.c:7:3: error: ‘cout’ is not a member of ‘std’
  </code></pre>
  
  <hr>
  
  <p>I have gone through several forums online but none of them seem to work for me :( </p>
  
  <p>This is a part of a bigger issue because of which one of my linux make doesn't work.</p>
  
  <p>Btw, I am using g++ and not gcc as a few posts messed up.</p>
  
  <hr>
  
  <p>EDIT 1:</p>
  
  <p>I changed the name to .cpp, and execute without sudo. Here is the verbose output:</p>
  
  <pre><code>pranoy@pranoyubuntu1210:~/Desktop/SIP/SIPp/sipp-3.3$ g++ -v test.cpp -o test
  Using built-in specs.
  COLLECT_GCC=g++
  COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.7/lto-wrapper
  Target: x86_64-linux-gnu
  Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 4.7.2-2ubuntu1' --with-bugurl=file:///usr/share/doc/gcc-4.7/README.Bugs --enable-languages=c,c++,go,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.7 --enable-shared --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.7 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --enable-plugin --enable-objc-gc --disable-werror --with-arch-32=i686 --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
  Thread model: posix
  gcc version 4.7.2 (Ubuntu/Linaro 4.7.2-2ubuntu1) 
  COLLECT_GCC_OPTIONS='-v' '-o' 'test' '-shared-libgcc' '-mtune=generic' '-march=x86-64'
   /usr/lib/gcc/x86_64-linux-gnu/4.7/cc1plus -quiet -v -imultiarch x86_64-linux-gnu -D_GNU_SOURCE test.cpp -quiet -dumpbase test.cpp -mtune=generic -march=x86-64 -auxbase test -version -fstack-protector -o /tmp/cczzibvL.s
  GNU C++ (Ubuntu/Linaro 4.7.2-2ubuntu1) version 4.7.2 (x86_64-linux-gnu)
      compiled by GNU C version 4.7.2, GMP version 5.0.2, MPFR version 3.1.0-p3, MPC version 0.9
  GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
  ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
  ignoring nonexistent directory "/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../../x86_64-linux-gnu/include"
  #include "..." search starts here:
  #include &lt;...&gt; search starts here:
   /usr/include/c++/4.7
   /usr/include/c++/4.7/x86_64-linux-gnu
   /usr/include/c++/4.7/backward
   /usr/lib/gcc/x86_64-linux-gnu/4.7/include
   /usr/local/include
   /usr/lib/gcc/x86_64-linux-gnu/4.7/include-fixed
   /usr/include/x86_64-linux-gnu
   /usr/include
  End of search list.
  GNU C++ (Ubuntu/Linaro 4.7.2-2ubuntu1) version 4.7.2 (x86_64-linux-gnu)
      compiled by GNU C version 4.7.2, GMP version 5.0.2, MPFR version 3.1.0-p3, MPC version 0.9
  GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
  Compiler executable checksum: 521527ea42f0901bf839bcaad0cb13e6
  test.cpp: In function ‘int main()’:
  test.cpp:5:3: error: ‘cout’ is not a member of ‘std’
  </code></pre>