通过命令行传递URL（C ++）

Question

I have c++ code which parses 2 command line arguments and prints the arguments. One of the argument is an URL of google search. I paste the code below

int main(int argc, char* argv[])
{
  std::cout << argv[1] << argv[2] << "\n";

}

When I pass URL through command line after compilation as below,

./demo 1 https://www.google.co.in/search?sourceid=chrome-psyapi2&ion=1&espv=2&ie=UTF-8&client=ubuntu&q=size%20of%20unsigned%20char%20array%20c%2B%2B&oq=length%20of%20unsigned%20char*%20arra&aqs=chrome.4.69i57j0l5.13353j0j7

I get the output as,

[1] 8680
[2] 8681
[3] 8682
[4] 8683
[5] 8684
[6] 8685
[7] 8686
[2]   Done                    ion=1
[3]   Done                    espv=2
[4]   Done                    ie=UTF-8
[6]-  Done                    q=size%20of%20unsigned%20char%20array%20c%2B%2B

It looks like there has been some internal splitting of the string. Is there any way I can retrieve the entire string?

Thank You in advance.

Answer 1

You have to quote it. Otherwise & gets interpreted by the shell as "invoke what's on the left of & in background".

I took the privilege of replacing your program with echo .

Good:

$ echo "https://www.google.co.in/search?sourceid=chrome-psyapi2&ion=1&espv=2&ie=UTF-8&client=ubuntu&q=size%20of%20unsigned%20char%20array%20c%2B%2B&oq=length%20of%20unsigned%20char*%20arra&aqs=chrome.4.69i57j0l5.13353j0j7"
https://www.google.co.in/search?sourceid=chrome-psyapi2&ion=1&espv=2&ie=UTF-8&client=ubuntu&q=size%20of%20unsigned%20char%20array%20c%2B%2B&oq=length%20of%20unsigned%20char*%20arra&aqs=chrome.4.69i57j0l5.13353j0j7

Bad:

$ echo https://www.google.co.in/search?sourceid=chrome-psyapi2&ion=1&espv=2&ie=UTF-8&client=ubuntu&q=size%20of%20unsigned%20char%20array%20c%2B%2B&oq=length%20of%20unsigned%20char*%20arra&aqs=chrome.4.69i57j0l5.13353j0j7
[1] 21705
[2] 21706
https://www.google.co.in/search?sourceid=chrome-psyapi2
[3] 21707
[4] 21708
[5] 21709
[6] 21710
[7] 21711
[1]   Done                    echo https://www.google.co.in/search?sourceid=chrome-psyapi2
[2]   Done                    ion=1
[3]   Done                    espv=2
[4]   Done                    ie=UTF-8
[5]   Done                    client=ubuntu
[6]-  Done                    q=size%20of%20unsigned%20char%20array%20c%2B%2B
[7]+  Done                    oq=length%20of%20unsigned%20char*%20arra

Answer 2

You need to quote the argument, and you should use single quotes, ' , in order to stop your shell from attempting to evaluate anything inside it.

What happens is that every ampersand, "&", on your command line launches a background process.

The first process is ./demo 1 https://www.google.co.in/search?sourceid=chrome-psyapi2 , and all the following are assignments to variables.

You can see from the output (it looks like you didn't post all of it)

[1] 8680
[2] 8681
[3] 8682
[4] 8683
[5] 8684
[6] 8685
[7] 8686
[2]   Done                    ion=1
[3]   Done                    espv=2
[4]   Done                    ie=UTF-8
[6]-  Done                    q=size%20of%20unsigned%20char%20array%20c%2B%2B

that background process 2 is ion=1 (pid 8681), process 3 (pid 8682) is espv=2 , and so on.