连续执行scanner.nextInt（）的问题

Question

我正在尝试使用scanner.nextInt（）分配两个变量L和R.赋值后，这些变量立即用于for循环。我的问题是扫描程序流在命令行保持打开状态，程序从不执行后续的for循环。这是一个片段：

 System.out.println("Enter the Left and Right endpoints: ");
 L = sc.nextInt();
 R = sc.nextInt();

 for (int i = L; i < R; i += resolution) {
   double a = i, b = resolution+i;
     if (poly(C, a)*poly(C, b) < 0) {
      double mid = findRoot(C, a, b, tolerance);
      System.out.println(mid);
      if (Math.abs(poly(C, mid)) < threshold){
        System.out.println("Root found at: "+mid);
        numCount = 1;
      }
   } else if (poly(D, a)*poly(D, b) < 0) {
      double mid = findRoot(D, a, b, tolerance);
      if(Math.abs(poly(C, mid)) < threshold) {
        System.out.println("Root found at: "+mid);
        numCount = 2;

   } else {
     numCount = 3;
     System.out.println("No roots were found in the specified range.");
   }
   System.out.println("numCount is "+numCount); break;
  }
}