n无法解析为变量

Question

I am completely new to java and hence was trying some simple programs by my self I am not able to get the output for the below program.

public class For_loop {
  public static void main(String[] args) {      
    int Sum = 0;        
    for (int n=0; n<=100; n++);         
        Sum= Sum +n; // getting the error here as n cannot be resolved to a variable
    {
    System.out.println (Sum);                           
    }       
  }     
}

Please help me with the output.

Answer 1

Remove semicolon ; in for loop. if you add semicolon it means completed statement and n variable scope limited to for..loop not outside.

  for (int n=0; n<=100; n++){
        Sum= Sum +n; 
  }

Answer 2

for the correct version of code.. please find below..

for (int n=0; n<=100; n++); on this line you r making the mistake. once you putting the semicolon. the loop end there. and you are defining the variable n as local variable having the visibility only to the for loop block. So when your are accessing the variable on the next line.. it gives you the error...

look below for the error free code...

for (int n=0; n<=100; n++)
{       
 Sum= Sum +n; 
}

Answer 3

As previously noted - the ; at your for() causes your loop to end there - making n unknown outside of this scope .

But even with that fixed, you still have a {} group in your code which is strange. Did you want to output sum on every iteration?

for (int n=0; n<=100; n++) { //where ; was before
    Sum +=n; // same as Sum = Sum +n; 
    System.out.println (Sum);        
}