// Using an array of pointers to functions
#include <iostream>
using namespace std;

// A macro to define dummy functions:
#define DF(N) void N() { \
       cout << "function " #N " called..." << endl; }

DF(a);
DF(b);
DF(c);
DF(d);
DF(e);
DF(f);
DF(g);

void (*func_table[])() = { a, b, c, d, e, f, g };

int main()
{
    while(1)
    {
        cout << "press a key from 'a' to 'g' "
             "or q to quit" << endl;
        char c, cr;
        cin.get(c);
        cin.get(cr); // second one for CR
        if ( c == 'q' )
        {
            break; // ... out of while(1)
        }
        if ( c < 'a' || c > 'g' )
        {
            continue;
        }
        (*func_table[c - 'a'])();
    }
}