int div(){
    int a1=3,b1=3,c1=3;
    int a2=1,b2=1,c2=1;
    if (a2==0 || b2==0 || c2==0) {
        printf ("Divide by zero!");
        return 0;
    }
    float x,y,z;
    x=a1/a2;
    y=b1/b2;
    z=c1/c2;
    if (x!=0) {
        if (x!=1) printf ("%fx^2 + ", x);
        else printf ("x^2 + ");
    }
    if (y!=0) {
        if (y!=1) printf ("%fx + ", y);
        else printf ("x");
    }
    if (z!=0) printf (" + %f", z);
    printf (" = 0");
}