java - 错误地使用for循环

在以下代码中，永远不会执行for循环。我试图用断点和监视来解决问题。返回的密文长度正确，但是for循环直到int i >= ciphertext.length()才增加。实际上，似乎在“调试”消息之后什么也没有执行。

private void decrypt_btnActionPerformed(java.awt.event.ActionEvent evt) {


    String alphabet= "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    String ciphertext="fRcXFBxXTRJ";


    status_label.setText( "Decryption has begun" );

    JOptionPane.showMessageDialog(null,"ciphertext-length: " + ciphertext.length() + "\n" + ciphertext,"Debug", JOptionPane.INFORMATION_MESSAGE);

    for (int i = 0; i>=ciphertext.length(); i--){

        System.out.println("inc:" + i);

        String cipher_current_char = getLetterAtIndex(ciphertext, i);
        int pos_char_in_alphabet = getIndexAtLetter(alphabet, cipher_current_char);


        if(pos_char_in_alphabet-2<0){

            plain_ta.setText(getLetterAtIndex(alphabet, (alphabet.length()+(pos_char_in_alphabet -2)+1 ) ));

            status_label.setText( 100/i + "%");



        }else{

            cipher_current_char = getLetterAtIndex(ciphertext, i);

            pos_char_in_alphabet = getIndexAtLetter(alphabet, cipher_current_char);

            plain_ta.setText(getLetterAtIndex(alphabet, (pos_char_in_alphabet-2)));

            status_label.setText( 100/i + "%");

        }
    }
}

最佳答案

for (int i = ciphertext.length()-1; i>=0; i--){

您需要向后工作。还要注意-1，您需要它来避免超出范围的异常（索引从0开始并转到length -1）。

遇到卡纸时，请始终用纸和铅笔大声圈出它，这总是有帮助的。

关于java - 错误地使用for循环，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/14573489/