Prоgramación factorial de un numero

#include

#include

#include

#define p printf

#define s scanf

main()

{

        int a, b, c, i, f, g;

        char x;

        do

        {

                system("cls");

        p("\tMenu Principal");

        p("\n1. Factorial");

        p("\n2. Fibonacci");

        p("\nSeleccione una opcion: ");

        s("%d", &a);

        switch(a)

                {

                        case 1: system("cls");

                                        c=1;

                                        p("\nIngrese el factorial que desea calcular");

                                        s("%d", &b);

                                        p("\n\nEl factorial es: \n");

                                        i=b;

                                        c=1;

                                        for(i;i>=1;i--)

                                                {

                                                        p(" %d ", i);

                                                        if(i!=1)

                                                        {

                                                                p(" x ");

                                                        }

                                                        c=c*(i);

                                                }

                                                p(" = %d ", c);

                                                p("\nDesea realizar otra operacion (s/n)?");

                                                s("%s", &x);

                                                if(x=='s'||x=='S')

                                                {

                                                        main();

                                                }

                                                else

                                                {

                                                        exit(0);

                                                }

                                        break;

...