Question

I am looking for a way to prepare a string for use as a URL.

The basics of the code is you type in what you are looking for and it opens a browser with what you typed in. I am learning C++, so this is a learning program. And please be as specific as possible for I am new to C++.

Here is what I am trying to do:

cin >> s_input;
transform(s_input.begin(), s_input.end(), s_input.begin(), tolower);
s_input = "start http://website.com/" + s_input + "/0/7/0";
system(s_input.c_str());

But I am trying to replace all the spaces the user enter with a ‘%20’. I have found one method this way but it only works with one letter at a time, and I am needing to do it with a full string and not an array of chars. Here is the method I have tried:

cin >> s_input;
transform(s_input.begin(), s_input.end(), s_input.begin(), tolower);
using std::string;
using std::cout;
using std::endl;
using std::replace;
replace(s_input.begin(), s_input.end(), ' ', '%20');
s_input = "start http://website.com/" + s_input + "/0/7/0";
system(s_input.c_str());

Thanks for your help!

Answer 1

If you have Visual Studio 2010 or later you should be able to use regular expressions to search/replace:

std::regex space("[[:space:]]");
s_input = std::regex_replace(s_input, space, "%20");

Edit: How to use the six-argument version of std::regex_replace:

std::regex space("[[:space:]]");
std::string s_output;
std::regex_replace(s_output.begin(), s_input.begin(), s_input.end(), space, "%20");

The string s_output now contains the changed string.

You might have to change the replacement string to std::string("%20").

As you see I have only five arguments, that’s because the sixth should have a default value.