#include <stdio.h>
#include <math.h>
int main()
{
printf("一、观察round函数\n");
printf("1.1 一位小数:保留一位小数\n");
printf("round(2.5)=%.1f\n", round(2.5));
printf("round(3.5)=%.1f\n", round(3.5));
printf("round(-2.5))=%.1f\n", round(-2.5));
printf("round(-3.5))=%.1f\n\n\n", round(-3.5));
printf("1.2 两位小数:保留一位小数\n");
printf("小数部分0.45:\n");
printf("round(2.45))=%.1f\n", round(2.45));
printf("round(3.45))=%.1f\n", round(3.45));
printf("round(-2.45))=%.1f\n", round(-2.45));
printf("round(-3.45))=%.1f\n\n", round(-3.45));
printf("小数部分大于0.45:\n");
printf("round(2.47))=%.1f\n", round(2.47));
printf("round(3.47))=%.1f\n", round(3.47));
printf("round(-2.47))=%.1f\n", round(-2.47));
printf("round(-3.48))=%.1f\n\n", round(-3.48));
printf("小数部分接近0.5:\n");
printf("round(2.499999999))=%.1f\n", round(2.499999999));
printf("round(3.499999999))=%.1f\n", round(3.499999999));
printf("round(-2.499999999))=%.1f\n", round(-2.499999999));
printf("round(-3.499999999))=%.1f\n\n", round(-3.499999999));
printf("查看数据类型匹配和不匹配的情况:\n");
printf("%d\n", round(-3.45));
printf("%f\n", 45);
printf("%d\n", 90.5);
printf("%d\n", 85555);
return 0;
}