当x<1,y=x当10>x>=1,y=2x-1当x>=10,y=3x-11
#include<stdio.h> int main() { double x,y; scanf("%lf",&x); if(x>=10)y=3*x-11; else if(x>=1)y=2*x-1; else y=x; printf("%lf",y); return 0 }