Execute .exe file from c++ code + enter values - c++

Question

I'm relatively new to c++, and I'm just making some simple programs.
One of my programs will need to open up a different .exe file. This .exe file will ask for 2 or 3 file names, then run and exit.
Just to test this out, I created a simple_calc.exe file, that ask for value1, then value2 then multiply them.
So let's say I want to create a "call_other_file.exe" and automatically run "simple_calc.exe" with value1 and value2 taken from "call_other_file.exe"s file.
How can I proceed to do that?
After searching a bit, i see something like:
system("simple_calc.exe -val1 -val2").
But that doesn't work for me. Or I'm not sure how to define val1 and val2...
edit: the program I want to access (simple_calc.exe in the example), I can not change the code there, I don't have access to it's .cpp file.
Any suggestions?

Answer 1

i see something like: system("simple_calc.exe -val1 -val2")
It should work. The reason why that didn't work might be that you didn't put int argc, char* argv[] in your "simple_calc"'s main function.
//simple_calc.cpp
int main(int argc, char* argv[])
{
if (argc == 2)
{
cout << "Error: At least two argument must be exist.";
return -1;
}
return 0;
// After that, you can use 'argv' arguments to calculate what you want to calculate. Also, in order to calculate them, you also need to convert 'argv' to integer or double, since they are string or char array.
}
For more information on C++ comand-line arguments see this site below:
http://www.tutorialspoint.com/cprogramming/c_command_line_arguments.htm
When you add the command-line arguments to your simple_calc.cpp, you can use this simple_calc.exe val1 val2. To call another program from your C++ program, you need system calls. In your main function;
system('simple_calc.exe')
You also need to know about how windows console work, if you are using windows. If you are using linux, its console commands are also different.
My suggestion is that you must first learn how consoles work different operating systems.

Answer 2

There are various ways to have two separate programs communicate with one another, but the system() function is probably the simplest; it just runs a string of text as though it were entered in a console window.
Basic example
The main program simply runs the other program with two arguments: hello and world.
/* main.c */
#include <stdlib.h>
int main() { return system("./other hello world"); }
The two arguments will be passed to the other program as C-style strings via the argv[] array. Note that they will be stored as the second and third elements, since the first item (argv[0]) will be the path to the program itself.
/* other.c */
#include <stdio.h>
int main(int argc, char *argv[])
{
int i = 0;
for (i = 1; i < argc; ++i) { printf("%s\n", argv[i]); }
return 0;
}
The output of the above programs will look like this:
hello
world
Process returned 0 (0x0) execution time : 0.004 s
Press ENTER to continue.
Arguments with spaces
As you may have noticed, arguments are space-separated. If you need to pass a string with spaces as a single parameter, you'll need to enclose it in quotes:
/* main.c */
#include <stdlib.h>
int main() { return system("./other \"this is all one string\" \"and so is this\" bye"); }
This would produce the following result:
this is all one string
and so is this
bye
Process returned 0 (0x0) execution time : 0.004 s
Press ENTER to continue.
Non-string arguments
Since the arguments are given as strings, you'll need to convert them into numbers (using conversion functions such as strtod(), atoi(), or atof()) if necessary. Here's an updated version of main.c:
/* main.c */
#include <stdlib.h>
int main() { return system("./other 4 6"); }
...and here's the corresponding other.c file:
/* other.c */
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
int total, i;
for (total = 0, i = 1; i < argc; ++i) { total += atoi(argv[i]); }
printf("TOTAL: %d\n", total);
return 0;
}
This produces the following output:
TOTAL: 10
Process returned 0 (0x0) execution time : 0.005 s
Press ENTER to continue.