illegal case 这是什么原因啊？求大佬解答

Question

while(keep1)
    {
        printf("请选择你需要的功能：");
        scanf("%d",input_sci);
        case 1:printf("sin");scanf("%lf",&num);c=num/180*3.14;printf("sin%g°=%.2f\n",num,sin(c));break;
        case 2:printf("cos");scanf("%lf",&num);c=num/180*3.14;printf("cos%g°=%.2f\n",num,cos(c));break;
        case 3:printf("tan");scanf("%lf",&num);c=num/180*3.14;printf("tan%g°=%.2f\n",num,tan(c));break;
        case 4:printf("ln");scanf("%lf",&num);printf("ln%g=%.2f\n",num,log(num));break;
        case 5:printf("lg");scanf("%lf",&num);printf("lg%g=%.2f\n",num,log10(num));break;
                                default:printf("输入错误\n");

}

Answer 1

在scanf语句后面加上

switch(input_sci){

最后一行哪里在加一个大括号}.

while(keep1)
{
    printf("请选择你需要的功能：");
    scanf("%d",input_sci);
	    switch(input_sci){
	    case 1:printf("sin");scanf("%lf",&num);c=num/180*3.14;printf("sin%g°=%.2f\n",num,sin(c));break;
	    case 2:printf("cos");scanf("%lf",&num);c=num/180*3.14;printf("cos%g°=%.2f\n",num,cos(c));break;
	    case 3:printf("tan");scanf("%lf",&num);c=num/180*3.14;printf("tan%g°=%.2f\n",num,tan(c));break;
	    case 4:printf("ln");scanf("%lf",&num);printf("ln%g=%.2f\n",num,log(num));break;
	    case 5:printf("lg");scanf("%lf",&num);printf("lg%g=%.2f\n",num,log10(num));break;
        default:printf("输入错误\n");
    }

}