title: Sum Series 23 45 67 89 Upto N Terms
signature: function sumSeries23456789UptoNTerms($n) {
test_code: <?php
  
  
  // SOLUTION CODE 
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  function validateSolution($actual, $expected){
      return abs($actual - $expected) < 1e-09;
  }
  
  function driver($n, $expected){
      try{
        if (validateSolution(PLACEHOLDER_FN_NAME($n), $expected)){
          return "PASSED";
        }
        return "FAILED";
      }
      catch (Exception $exception_obj) {
        return get_class($exception_obj);
      }
  }
  
  function main(){
      printf("TEST-0...%s\n",driver(
        49, 
        0.7803986631477524));
      
      printf("TEST-1...%s\n",driver(
        4, 
        -0.16507936507936516));
      
      printf("TEST-2...%s\n",driver(
        60, 
        -0.21050375120783382));
      
      printf("TEST-3...%s\n",driver(
        90, 
        -0.21185466678122022));
      
      printf("TEST-4...%s\n",driver(
        96, 
        -0.2120245854859959));
      
      printf("TEST-5...%s\n",driver(
        29, 
        0.7770671416747363));
      
      printf("TEST-6...%s\n",driver(
        86, 
        -0.21172836828074082));
      
      printf("TEST-7...%s\n",driver(
        47, 
        0.780190394898247));
      
      printf("TEST-8...%s\n",driver(
        77, 
        0.7821931668684383));
      
      printf("TEST-9...%s\n",driver(
        87, 
        0.7825573460049735));
      
  }
  
  main();
  ?>
source_py: def sum_series_23_45_67_89_upto_n_terms(n):
      i = 1
      res = 0.0
      sign = True
      while (n > 0):
          n = (n - 1)
          if sign:
              sign = False
              res = (res + ((i + 1) / (i + 2)))
              i = (i + 2)
          else:
              sign = True
              res = (res - ((i + 1) / (i + 2)))
              i = (i + 2)
      return res
source_cpp: double sum_series_23_45_67_89_upto_n_terms(int n) {
    int i = 1;
    double res = 0.0;
    bool sign = true;
    while ( n > 0 ) {
      n --;
      if ( sign ) {
        sign = ! sign;
        res = res + ( double ) ++ i / ++ i;
      }
      else {
        sign = ! sign;
        res = res - ( double ) ++ i / ++ i;
      }
    }
    return res;
  }