计算成绩

#include<stdio.h>
int main()
{
    float score;
    scanf("%f",&score);
    if(90<=score&&score>=100)
        printf("优\n");
    else if(80<=score&&score<90)
        printf("良\n");
    else if(70<=score&&score<80)
        printf("中\n");
    else if(60<=score&&score<70)
        printf("差\n");
    else if(score<60)
        printf("不及格\n");

    else
        printf("数据非法\n");
    return 0;
}