String output="\n"和String outpu+="\n";program code
import javax.swing.JOptionPane;
public class MultiplicationTable{
public static void main(String args[]){ String output=" MultiplicatonTable\n";
output+="----------------------------------------------------------\n";
output+=" |";
for(int j=1;j<=9;j++)
output+=" "+j;
[b]output+="\n";for(int i=1;i<=9;i++) {
output+=i+" | ";
for(int j=1;j<=9;j++) {if(i*j<10)
output+=" "+j*i;
else
output+=" "+i*j;
}
output+="\n";
}
JOptionPane.showMessageDialog(null,output);
}
}
import javax.swing.JOptionPane;
public class MultiplicationTable{
public static void main(String args[]){ String output=" MultiplicatonTable\n";
output+="----------------------------------------------------------\n";
output+=" |";
for(int j=1;j<=9;j++)
output+=" "+j;
[b]output+="\n";for(int i=1;i<=9;i++) {
output+=i+" | ";
for(int j=1;j<=9;j++) {if(i*j<10)
output+=" "+j*i;
else
output+=" "+i*j;
}
output+="\n";
}
JOptionPane.showMessageDialog(null,output);
}
}
一般都是
String output="\n"
这个是已经定义了
操作outpu+="\n"; ===outpu=output+"\n";
这个申明是错误的
import javax.swing.JOptionPane;
public class MultiplicationTable{
public static void main(String args[]){ String output=" MultiplicatonTable\n";
output+="----------------------------------------------------------\n";
output+=" |";
for(int j=1;j<=9;j++)
output+=" "+j;
output+="\n"; \\ 这一行我存在疑问, 觉得output="\n"也可以, 可是运行后 出现的界面和output+="\n"完全不一样了for(int i=1;i<=9;i++) {
output+=i+" | ";
for(int j=1;j<=9;j++) {if(i*j<10)
output+=" "+j*i;
else
output+=" "+i*j;
}
output+="\n";
}
JOptionPane.showMessageDialog(null,output);
}
}