如何在Java中将包含3的数组替换为4？

Question

void replace3sWith4s(int[] replace){
  for (int i = 0;i<replace.length;i++){
      if (replace[i]==3);{
          replace[i]=4;
      }
  }
}

My program is replacing all numbers with #4 but I want to have an array that contains 3, takes an integer array, and changes any element that has the value 3 to instead have the value 4.

Answer 1

if (replace[i]==3);
                 ^^^

Remove the semicolon. It should be

if (replace[i]==3) {
      replace[i]=4;
}

The semicolon changes the meaning to

if (replace[i]==3)
    ;//do nothing

// Separate New block
{
    replace[i]=4;
}

Answer 2

(replace[i]==3); 

Is like writing

(replace[i]==3) { }

Which does nothing.

Your code is equivalent to this code:

void replace3sWith4s(int[] replace){
  for (int i = 0;i<replace.length;i++){
      if (replace[i]==3) { }
      replace[i]=4;  //Always reachable
      }
  }
}

To fix your code, remove the semicolon:

(replace[i]==3); 
               ^

Answer 3

also You can try this method at if statement according to your array type

if (replace[i].equals("3")){

replace[i]=4;   

}