main function giving error warning

Question

Why does microsoft visual studio underline int with redline saying

"IntelliSense: PCH warning: cannot find a suitable header stop location. An intellisense PCH file was not generated" for this code.

int main(){
    return 0;
}

It runs fine

Answer 1

IntelliSense is the system the pops up the drop-down list with possible code completions.

A PCH (precompiled header) is a file generated by the compiler to speed up repeated compilation.

IntelliSense is telling you that it will be unbearably slow because you haven't configured PCH for your project. Nothing more.