c++ using system command problem

Question

hi every body i have a strange problem i write a code in c++ complied it successfully and run it successfully. i compiled with following command g++ 1.c -o abc to run program i use ./abc now my problem is that i write a another code in c++ like

#include <fstream>
#include<iostream>
using namespace std;
int main()
{
  ofstream SaveFile("/home/hadoop/project/hadoop-0.20.0/conf/core-site2.xml");
  SaveFile <<"<configuration>";
  SaveFile<<endl;
  SaveFile<<"<property>";
  SaveFile<<endl;
  savefile.close();
  return 0;
}

now i want to run abc in this code how to do this ? how to use or run abc in this file? how to use ./abc in this program ?

i accept most of the answers given by you but i dont know how to tell that i accept the answer please expalin me what should i do — user513164
– user513164, Commented Mar 22, 2011 at 5:43
@user513164, acceptance has a specific meaning here - it means clicking on the big open green tick mark to the left of an answer. This will then become a filled-in big green tick mark and "reward" the owner of that answer with 15 points. — paxdiablo
– paxdiablo, Commented Mar 22, 2011 at 5:45
In the answer that you find best solves your problem, click on the check mark on the left side to mark an answer as correct. — Varun Madiath
– Varun Madiath, Commented Mar 22, 2011 at 5:46

paxdiablo · Accepted Answer · 2011-03-22 07:40:27Z

1

Actually, your question title ("... using system ...") says it all. Use:

system ("./abc");

to run the ./abc program.

There are other ways to run programs from within a program (which usually depend on platform-specific features) but this is the most portable.

A full sample program, testprog.cpp, to show what I mean:

#include <cstdlib>
int main (void) {
    std::system ("ls -ald m*");
    return 0;
}

Compiling this with:

g++ -Wall -Wextra -pedantic -o testprog testprog.cpp

and running the resultant executable testprog, this outputs (on my Ubuntu 10.04 box):

drwxr-xr-x 2 pax pax 4096 2010-12-14 09:33 myfolder

In other words, it runs the ls -ald m* command from within the program itself.

edited Mar 22, 2011 at 7:40

answered Mar 22, 2011 at 5:42

paxdiablo

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5 Comments

user513164 Over a year ago

thanks for your answer please explain them i'm using ubuntu 10.04

dreamlax Over a year ago

@user513164: Have a look at fork() and the exec family.

user513164 Over a year ago

i used the command but its generate an error ‘system’ was not declared in this scope tell me what should i do

paxdiablo Over a year ago

@user513164, you need to include cstdlib as per the code given. Otherwise the compiler doesn't know about system(). If I comment out that line, I similarly get: testprog.cpp:3: error: ‘system’ was not declared in this scope.

filmor Over a year ago

If you use C++ and include cstdlib you are only guaranteed to have system in namespace std, so use std::system.

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