#include <stdio.h>


int main()
{
    float y,x,t;
    x=0;
    t=0;
    prinf("请输入X的值：%f",x)；
    scanf("%f",&x);
    if    {
        (x<0)
        printf("x的值不可以小于0");
            if {
                (t<=x)
                t=t+1;
            else
                t=t-1;
                    if{
                        (t=t+0.1<=x)
                        t=t+0.1;
                    else
                        t=t-0.1;
                            if{
                                (t=t+0.01<=x)
                                t=t+0.01;
                            else
                                t=t-0.01;
                                    if{
                                        (t=t+0.001<=x)
                                        t=t+0.001;
                                    else
                                        t=t-0.001;
                                    }
                            }
                       }
                    }   
            
    else
        printf("y=%f",y);
    return 0;
}

谢谢啊，我昨晚睡着了，今早上课的，没来得及回复，抱歉啊

谢谢