c++ - Eclipse C.D.T. can't recognize standard functions or "NULL" -

i have been having problem weeks , have not been able find solution.

when trying use eclipse or trying compile plain gcc or g++ through terminal, there number of standard functions (plus "null" variable) not recognized, including to_string method.

i have attempted add many different headers program in attempt find correct files, no avail. have tried #including <string>, <stdio.h>, <stddef.h>, <cstdlib>, , pretty other standard header find in forum posts might contain to_string function. tried of these #includes , without ".h" extension. still, not matter tried, to_string , null not recognized (among other methods).

i've been through many forums , many forum posts , tried many solutions, including this one, this one, this one, this one, this one, , more. still, have found no solution.

i have tried uninstalling , reinstalling eclipse c.d.t., eclipse whole, gcc, , g++. have tried adding -std=c++11 and/or -std=c++99 flags gcc command or g++ command. have tried building in eclipse linux gcc, cross gcc, , other versions of gcc.

i running eclipse 3.8 both j.d.t. , c.d.t. packages installed on 64-bit linux mint 16 petra.

if me resolve issue, "grateful" not express gratitude toward you.

edit: here output of gcc -v:

using built-in specs. collect_gcc=gcc collect_lto_wrapper=/usr/lib/gcc/x86_64-linux-gnu/4.8/lto-wrapper target: x86_64-linux-gnu configured with: ../src/configure -v --with-pkgversion='ubuntu/linaro 4.8.1-10ubuntu9' --with-bugurl=file:///usr/share/doc/gcc-4.8/readme.bugs --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.8 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.8 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64 --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.8-amd64 --with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --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 4.8.1 (ubuntu/linaro 4.8.1-10ubuntu9) 

here's sample of code code having errors. please keep in mind have attempted add other #includes not shown , have reason believe missing #include not problem.

#include <string> #include <stdio.h> #include <iostream>  using namespace std;  int month[13] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };  string x;  class date_time { private:     int minute, hour, day, month, year; public:      date_time(int minute, int hour, int day, int month, int year) {         this->minute = minute;         this->hour = hour;         this->day = day;         this->month = month;         this->year = year;     }      string tostring() {         string min = to_string(minute);         if (min.length() == 1)             min = '0' + min;          return to_string(month) + "/" + to_string(day) + "/" + to_string(year)                 + " " + to_string(hour) + ":" + min;      }      void addminutes(int min) {          minute = min + minute;         if (minute > 59) {             minute = minute - 60;             hour = hour + 1;         }         if (hour > 24) {             hour = hour - 24;             day = day + 1;         }          if (day > month[month])             day = day - month[month];         month = month + 1;          if (month > 12) {             month = 1;             year = year + 1;          }     }      int getyear() {         return year;     }      int getmonth() {         return month;     }      int getday() {         return day;     }      int gethour() {         return hour;     }      int getminutes() {         return minute;     }  }; 

edit: summary of comments below have determined cause eclipse not recognizing c++11 standard functions , keywords. installed netbeans on system c/c++ plugin , exact same errors occurring. can't seem netbeans or eclipse recognize c++11 features despite adding -std=c++11 flag in multiple places in project configurations.

as of right now, eclipse can compile without giving c++11 errors; however, in code window, c++11 functions , features still marked errors red underline, issue still not resolved. need tell me how eclispe and/or netbeans recognize c++11 features in error parsers.

thanks again in advance may able provide.

try compile source code with

g++ -std=c++11 ... 

according to_string(), c++ 2011 feature.

---

in eclipse kepler, set selecting

project >> properties >> c/c++ build >> settings >> tool settings >> gcc c++ compiler >> dialect

and choosing iso c++11 (-std=c++0x) language standard.

and should choose [all configurations] configuration @ c/c++ build.