在下面的代码中,for 循环永远不会被执行。我尝试通过断点和监视来解决问题。返回密文的正确长度,但是 for 循环直到 int i >= ciphertext.length()
才会递增。事实上,除了“调试”消息之外,似乎没有任何内容执行。
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--){
你需要逆向工作。另请注意 -1
,您需要它来避免越界异常(索引从 0
开始并转到 length -1
)。
当你遇到困难时,总是用纸和铅笔大声地描绘出你的循环,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/