#include <iostream>
#include <fstream>
 
using namespace std;
 
int main ( int argc , char *argv[])
{
    ifstream file;
    file.open("test",ifstream::in );
    char extraction [100];
    file.getline(extraction,40,'~');
    cout << extraction;
    file.close();
    return 0;
}

12345~aeiou

12345

for(int i=0;i<texto.length();i++){
        if(texto[i]=='\\' && texto[i+1]=='n'){
            texto.replace(i,2,"\n");
        }
    }

if(texto[i]=='~'){
            texto.replace(i,1,"\n");
        }