程序怎么写呢？怎么让他运行下去

float fun(float x){

    if(x<=1){
        return x;

    }else if(x>1 && x<10){
        return 2*x-1;
    }else{
        return 3*x-11;
    }

}

float fun(float x)
{
	float y;
	if (x <= 1)
		y = x;
	else if (x > 1 && x <= 10)
		y = 2 * x - 1;
	else
		y = 3 * x - 11;
	return y;
}

if(x<=1){
    return x;
}else if(x>1 && x<10){
    return 2*x-1;
}else{
    return 3*x-11;
}