c语言PTA7-14 函数编程-分段函数 (15分)

#include
#include
int main()
{
    double hanshu(double a);
    double x;
    scanf("%lf",&x);
    double y;
    int a=0;
    if(x<=-2){
	y=-exp(2*x+1)+3;
	a=1;
	}
    if(x>3){
    y=hanshu(x);
    a=1;
	}
	if(a==0)printf("y=%.6lf",2*x-1);
	if(a==1)
    printf("y=%.6lf",y);
    return 0;
}
double hanshu(double a){
    double b;
    if(a>3)b=2*log10(3*a+5)-11;
    return b;
}