Visual studio 2019 slow debug build with for loop

Question

Hello
I was trying to debug a program with Visual Studio 2019 v142 with 10.0.19041.0 SDK, C++17 Standard
stepping through lines is ok but it's clearly slower at the execution of loops with many iterations such as this:

    ifstream in("text.txt");
    vector <string > words_to_find= {"apple", "monkey"};
    vector <pair<string, int>> matches;
    string line;
    while (getline(in, line))
    { 
        for (int g = 0; g < words_to_find.size(); g++)
        {
            int ret = line.find(words_to_find[g]); 
            if (ret  != string::npos)
            { 
                matches.push_back({words_to_find[g], (int)in.tellg()} );
            }
        }
    }

to complete the loop the debug version takes 14 seconds and the release version 2.5 seconds, and it's the same even if i just run the executables from a normal command line
any help?
thanks

Answer 1

Why would you expect a debug build of an executable to run as quickly as a release build?

In a debug build the compiler performs no optimizations; release builds contain optimized code. And, a debug build will include certain checks during execution that are not present in a release build.