Reading file in C++ until string
Unnecessary #includes:

You don't need &lt;cstdlib&gt; and &lt;iomanip&gt; for this program. Those can be removed.

Avoid using namespace:

using namespace in a source file for such a tiny program is fine, but don't make it a habit. Prefer to qualify the names with the namespace prefix (std::) when practical. Read a longer discussion here.

Open the stream on declaration and let the destructor close it:

Instead of explicitly calling open() in your file, use the parameterized constructor to make your code more concise and direct:

std::ifstream file("in.txt");


Also, no need to explicitly close at the end of main(). The destructor will close the file automatically when the scope of declaration is exited.

Be sure to always check that the file was opened successfully! If it fails, you should at least print a message to let the user know about the problem.

Use the return value of getline() instead of eof():

The canonical line reading loop in C++ is:

while (std::getline(file, line)) 
{
}


That can simplify you program quite significantly. You can still test specific error states with the methods bad(), fail() and eof(). See the documentation for std::ifstream.

Incorrect use of string::find():

You have misinterpreted the return value of std::string::find(). This method returns the position of the first character of the first match. If no matches were found, the function returns std::string::npos.

Which means that testing it as in if (temp.find(delimet)) will probably not work as you intended, since the return value is not a boolean.

The correct usage is:

if (str.find(substring) != std::string::npos) { /* found the substring */ }


Also note that "member - modal" is not the same as "member-modal". find() will look for an exact match, including spaces, so your implementation will only find something in the input file if you replace the search string to match the contents of the file down to each space. A more flexible implementation could be achieved using C++ regular expressions. 

Be more thoughtful about variable naming:

Names line temp and delimet convey little meaning. 

temp should at the very least be named line, as that is what the variable holds (a line from the file). 

delimet sounds like a misspelled "delimiter", so delimiter would be better. Other options include needle, for searching a needle in a haystack, target, for the target of the search, wanted_string, and the list goes on...

Properly indent main():

Code inside main() is not properly indented to convey nesting into the function. Proper indentation is very important for code readability, so that must be fixed.

Summing up:

This is my suggest implementation, based on the original code and applying the above changes:

#include &lt;fstream&gt;
#include &lt;iostream&gt;
#include &lt;string&gt;

int main()
{
    // Alway check after opening to make sure the
    // file existed and was opened successfully.
    //
    std::ifstream file("in.txt");
    if (!file.is_open())
    {
        std::cerr &lt;&lt; "Failed to open file!\n";
        return -1;
    }

    // Since this is a read-only variable,
    // also mark is as `const` to make intentions
    // clear to the readers.
    //
    const std::string needle = "member-modal";

    // Main reading loop:
    //
    std::string haystack;
    while (std::getline(file, haystack))
    {
        if (haystack.find(needle) != std::string::npos)
        {
            std::cout &lt;&lt; haystack &lt;&lt; "\n";
            // Prints 
            //  &lt;a class="member-modal" href="https://website.net/users/membercard/890520"&gt;Phil Jankins&lt;/a&gt;
            // once
        }
    }
}