Cfrgtkky

I'm practically done with my project, all I need now is to write a bash script that should compile and execute the program. My instructions are that we should provide a script that should compile the program and the instructor should be able to run the program by typing in Project1 Value1 Value2. I'm kinda lost on this one, so any help would be appreciated.

I have tried to compile the program by running this script

#!/bin/bash

echo $1

echo $2

g++ -std=c++11 Project2.cpp -lpthread -o project1

./project1 $1 $2

Edit

#!/bin/bash

g++ -std=c++11 Project2.cpp -lpthread -o project1

I thought about it a bit more, and I think my second version is closer to what I would like my script to do. Except I was hoping to be able to execute the program without using ./ if possible.

You have struggled for a few hours and put something together, but what happens if the compilation fails? What happens if there are no arguments? What happens if there are 4 arguments for the program?

When writing a script, or a program, the most important thing you can do is validate every necessary step! If you are expecting input, validate you received it. Once you have the input, validate it is what your expected. Is it a value within the usable range? Is it a filename that meets my requirements? Does it exist? Did my compile succeed or fail? Do I try and execute the program?

All of these need to be addressed. Otherwise, your script (or program) will stray off on some undefined path.

Bash provides a wealth of conditional expressions that can be used with test (or [...]) or using the bash [[...]] operator. See Bash Manual - 6.4 Bash Conditional Expressions. Make use of the language features to make your code robust.

Bash provides a wealth of string handling features through parameter expansions Bash Manual - 3.5.3 Shell Parameter Expansion, use them to check the extension to make sure it is c, cpp or c++

Putting those features together with a few if...then...fi statements will make your script much more reliable -- and actually do what it is you are trying to do.

The following short script takes arguments (bash Positional Parameters) requiring that at least the filename to compile be provided, and passing any additional arguments to the compiled program as command line arguments with ${@:2} (all bash positional parameters beginning with the 2nd one)

#!/bin/bash



if [ -z "$1" ]      ## validate at least one argument given

then

    printf "error: insufficient argumentsn" >&2

    printf "usage: %s file.cpp [args]n" "${0##*/}" >&2

    exit 1

fi



if [ ! -r "$1" ]    ## validate file is readable

then

    printf "error: file not found '%s'n" "$1" >&2

    exit 1

fi



src="$1"    ## give source file a handy name



## check the source file ends in '.c', '.cpp' or '.c++'

if [ "${src##*.}" != 'c' -a "${src##*.}" != 'cpp' -a "${src##*.}" != 'c++' ]

then

    printf "error: first argument not a c/c++ filen" >&2

    exit 1

fi



ext="${src##*.}"        ## save the extension



if [ "${#ext}" = 'c' ]  ## check if ext is 'c' use gcc else use g++

then

    ## always enable compiler warnings, -Wall -Wextra -pedantic, minimum

    #  -Wshadow to catch shadowed variables, -Werror treat warnings as error

    gcc -Wall -Wextra -pedantic -Wshadow -Werror 

        -std=c11 -O3 -o "${src%.*}" "$src"

else

    g++ -Wall -Wextra -pedantic -Wshadow -Werror 

        -std=c++11 -O3 -o "${src%.*}" "$src"

fi



if [ $? -eq '0' ]       ## check the compiler return, run only on success

then

    ./"${src%.*}" ${@:2}

else

    printf "nAn error occurred, executable not callednn" >&2

fi

Now a couple of short examples to make sure it works:

#include <stdio.h>



int main (int argc, char **argv) {



    const char *s = "hello c file.";



    printf ("%sn", s);



    for (int i = 1; i < argc; i++)

        printf ("arg[%d]: %sn", i, argv[i]);

}

Example Use/Output

$ bash compilewargs.sh cfile.c foo bar baz

hello c file.

arg[1]: foo

arg[2]: bar

arg[3]: baz

For C++

#include <iostream>

#include <string>



int main (int argc, char **argv) {



    std::string s = "hello cpp file.";



    std::cout << s << 'n';



    for (int i = 1; i < argc; i++)

        std::cout << "arg[" << i << "]: " << argv[i] << 'n';

}

Example Use/Output

$ bash compilewargs.sh cppfile.cpp foo bar baz

hello cpp file.

arg[1]: foo

arg[2]: bar

arg[3]: baz

Does the error-handling work?

#include <stdio.h>



int main (void) {



    const char *s = "hello c file.";



    printf ("%sn", unknown);

}

Example Use/Output

$ bash compilewargs.sh cerrfile.c foo bar baz

cerrfile.c: In function ‘int main()’:

cerrfile.c:7:21: error: ‘unknown’ was not declared in this scope

     printf ("%sn", unknown);

                     ^

cerrfile.c:5:17: error: unused variable ‘s’ [-Werror=unused-variable]

     const char *s = "hello c file.";

                 ^

cc1plus: all warnings being treated as errors



An error occurred, executable not called

What about a file that doesn't exist?

$ bash compilewargs.sh myfile.c foo bar baz

error: file not found 'myfile.c'

What about a text (or any other non-c, cpp or c++) file?

$ bash compilewargs.sh compilewargs.sh foo bar baz

error: first argument not a c/c++ file

By taking the time to think though what the dumbest user you know could ever try and do with your script -- and protecting against it, you can write reasonably robust scripts that will save you grief. Look things over and let me know if you have further questions.

I ended up figuring it out after a while.

#!/bin/bash

echo "Enter TP"

read TP

echo "Enter TC"

read TC

g++ -std=c++11 Project_1.cpp -lpthread -o Project_1

./Project_1 $TP $TC