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POWhy do I have "Type mismatch; Found Unit, expected Boolean" in Scala-IDE?
 

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  1. POWhy do I have "Type mismatch; Found Unit, expected Boolean" in Scala-IDE?
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    <p>I've got the following Scala code(ported from a Java one):</p> <pre><code>import scala.util.control.Breaks._ object Main { def pascal(col: Int, row: Int): Int = { if(col &gt; row) throw new Exception("Coloumn out of bound"); else if (col == 0 || col == row) 1; else pascal(col - 1, row - 1) + pascal(col, row - 1); } def balance(chars: List[Char]): Boolean = { val string: String = chars.toString() if (string.length() == 0) true; else if(stringContains(")", string) == false &amp;&amp; stringContains("(", string) == false) true; else if(stringContains(")", string) ^ stringContains("(", string)) false; else if(getFirstPosition("(", string) &gt; getFirstPosition(")", string)) false; else if(getLastPosition("(", string) &gt; getLastPosition(")", string)) false; else if(getCount("(", string) != getCount(")", string)) false; var positionOfFirstOpeningBracket = getFirstPosition("(", string); var openingBracketOccurences = 1; //we already know that at the first position there is an opening bracket so we are incrementing it right away with 1 and skipping the firstPosition variable in the loop var closingBracketOccurrences = 0; var positionOfClosingBracket = 0; breakable { for(i &lt;- positionOfFirstOpeningBracket + 1 until string.length()) { if (string.charAt(i) == ("(".toCharArray())(0)) { openingBracketOccurences += 1; } else if(string.charAt(i) == (")".toCharArray())(0) ) { closingBracketOccurrences += 1; } if(openingBracketOccurences - closingBracketOccurrences == 0) { //this is an important part of the algorithm. if the string is balanced and at the current iteration opening=closing that means we know the bounds of our current brackets. positionOfClosingBracket = i; // this is the position of the closing bracket break; } } } val insideBrackets: String = string.substring(positionOfFirstOpeningBracket + 1, positionOfClosingBracket) balance(insideBrackets.toList) &amp;&amp; balance( string.substring(positionOfClosingBracket + 1, string.length()).toList) def getFirstPosition(character: String, pool: String): Int = { for(i &lt;- 0 until pool.length()) { if (pool.charAt(i) == (character.toCharArray())(0)) { i; } } -1; } def getLastPosition(character: String, pool: String): Int = { for(i &lt;- pool.length() - 1 to 0 by -1) { if (pool.charAt(i) == (character.toCharArray())(0)) { i; } } -1; } //checks if a string contains a specific character def stringContains(needle: String, pool: String): Boolean = { for(i &lt;- 0 until pool.length()) { if(pool.charAt(i) == (needle.toCharArray())(0)) true; } false; } //gets the count of occurrences of a character in a string def getCount(character: String, pool: String) = { var count = 0; for ( i &lt;- 0 until pool.length()) { if(pool.charAt(i) == (character.toCharArray())(0)) count += 1; } count; } } } </code></pre> <p>The problem is that the Scala IDE(lates version for Scaal 2.10.1) gives the following error at line 78(on which there is a closin brace): "Type mismatch; Found Unit, expected Boolean". I really can't understand what the actual problem is. The warning doesn't give any information where the error might be.</p>
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    1. COBy the way, if you are doing coursera task, you definitely overthinking the problem (and your code contains some really bad flaws, e.g. in `stringContains` code will always return `false`).
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      1. POWhy do I have "Type mismatch; Found Unit, expected Boolean" in Scala-IDE?
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    2. COOr underthinking, depending on how you look at it. This is a great example of how you can save a little design effort and buy a ton of implementation complexity for it.
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      1. POWhy do I have "Type mismatch; Found Unit, expected Boolean" in Scala-IDE?
      1. USthemel
 

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