在课本【例2-4】中,如果要增加一个出错处理机制,当输入的用水量x小于0时,打印提示语句"输入数据有误",下列哪个程序段可以正确地使用else-if语句实现该功能?
A.
if(x<=0) printf(" 输入数据有误 \n"); else if(x<=15) {y=4*x/3; printf("y=f(%f)=%.2f\n",x,y);} else {y=0.25*x-10.5; printf("y=f(%f)=%.2f\n",x,y);}
B.
if(x<0) printf(" 输入数据有误 \n"); else if(0<=x<=15) {y=4*x/3; printf("y=f(%f)=%.2f\n",x,y);} else {y=0.25*x-10.5; printf("y=f(%f)=%.2f\n",x,y);}
C.
if(x<0) printf(" 输入数据有误 \n"); else if(x<=15) {y=4*x/3;} else {y=0.25*x-10.5;} printf("y=f(%f)=%.2f\n",x,y);
D.
if(x<0) printf(" 输入数据有误 \n"); else if(x<=15) {y=4*x/3; printf("y=f(%f)=%.2f\n",x,y);} else {y=0.25*x-10.5; printf("y=f(%f)=%.2f\n",x,y);}