# include <stdio.h>
void main()
{
int x, y;
printf("请输入自变量x:");
scanf("%d", &x);
if(x < 6)
{
y = x - 12;
printf("x = %d, y = %d\n", x, y);
}
else if(x < 15)
{
y = 3*x - 1;
printf("x = %d, y = %d\n", x, y);
}
else
{
y = 5*x + 9;
printf("x = %d, y = %d\n", x, y);
}
}