Convert string to Macros in C++

Question

I want to print the value of my macros through a string Given Code

#include<iostream>
#define abc 7

using namespace std;

int main()
{
 string str = "abc";
 cout<<str<<endl;
}

Output should be 7 if i do cout str

since macros are just replaced with their values, how about `cout< — Gaurav Sehgal, Oct 09 '17 at 08:40
The problem is - i will read the str value from a file and there will be multiple macros in that file — Deepanshu Bhatti, Oct 09 '17 at 08:43
Bad question (very unclear), lacking some [MCVE](http://stackoverflow.com/help/mcve). You could consider some [X macro](https://en.wikipedia.org/wiki/X_Macro) — Basile Starynkevitch, Oct 09 '17 at 08:47

score 3 · Accepted Answer · answered Oct 09 '17 at 08:50

You cannot. Macro expansion occurs in early translation phases before actual compilation. That means that your requirement cannot be achieved in C++. But std::map (or std::unordered_map) is a associative container implementation that can be used to convert strings at run-time

Convert string to Macros in C++

1 Answers1