楼主好~（保留两位小数）main(){ double a,b;char x;printf("input:\n");scanf("%lf%c%lf",&a,&x,&b);switch(x){ case '+': printf("%.2lf\n",a+b); break;case '-': printf("%.2lf\n",a-b); break;case '*': printf("%.2lf\n",a*b); break;cas...