c语言学习

int main16(){
	int score = 0;
	
	printf("	输入一个分数:");
	scanf("%d", &score);
	
	if(score >= 90 && score <= 100) {
		
		
		
		if(score >= 90 && score <= 100){  printf("优秀\n");}
		else if(score >= 80 && score <= 89){  printf("良好\n"); }
		else if(score >= 70 && score <= 79){  printf("中等\n"); }
		else if(score >= 60 && score <= 69){  printf("及格\n"); }
		else {  printf("不及格\n");} 
	}
	else {	printf("错误\n");}	
}