#include "stdio.h"
main()
{
int x,y;
scanf("%d",&x);
if (x<1) y=x;
else if (x<10) y=2*x-1;
else y=3*x-11;
printf("%d",y);
}
少了乘号*
#include "stdio.h"
main()
{
int x,y;
scanf("%d",&x);
if (x<1) y=x;
else if (1<=x<10) y=2*x-1; /*在这个地方改一下*/
else y=3*x-11; /*在这个地方改一下*/
printf("%d",y);
}