title: Replace Character C1 C2 C2 C1 String S
signature: function replace_character_c1_c2_c2_c1_string_s(s, c1, c2)
test_code: using Printf
  
  # SOLUTION CODE
  # ============================================
  PLACEHOLDER_CODE_BODY
  
  # TESTING CODE 
  # ============================================
  function validate_solution(actual, expected)
      return actual == expected
  end
  
  function driver(s, c1, c2, expected)
      try
  
          if validate_solution(PLACEHOLDER_FN_NAME(s, c1, c2), expected)
              return "PASSED";
          end
          return "FAILED";
      catch exception_obj
          return string(Base.typename(typeof(exception_obj)).wrapper);
      end
  end
  
  function main()
      
      result = driver("IZTSMw j", 'W', 'k', "IZTSMw j");
      @printf("TEST-0...%s\n",result);
      
      result = driver("7288334", '6', '9', "7288334");
      @printf("TEST-1...%s\n",result);
      
      result = driver("010110000", '1', '1', "010110000");
      @printf("TEST-2...%s\n",result);
      
      result = driver("b gJX", 't', 'P', "b gJX");
      @printf("TEST-3...%s\n",result);
      
      result = driver("734", '4', '4', "734");
      @printf("TEST-4...%s\n",result);
      
      result = driver("1", '1', '1', "1");
      @printf("TEST-5...%s\n",result);
      
      result = driver("xCaUKdhA", 'X', 'S', "xCaUKdhA");
      @printf("TEST-6...%s\n",result);
      
      result = driver("4370992644981", '5', '6', "4370992544981");
      @printf("TEST-7...%s\n",result);
      
      result = driver("01010", '0', '1', "10101");
      @printf("TEST-8...%s\n",result);
      
      result = driver("ZNIFGshaWA", 'Q', 'x', "ZNIFGshaWA");
      @printf("TEST-9...%s\n",result);
      
  end
  
  main()
source_py: def replace_character_c1_c2_c2_c1_string_s(s, c1, c2):
      l = len(s)
      for i in range(l):
          if (s[i] == c1):
              s = ((s[0:i] + c2) + s[(i + 1):])
          elif (s[i] == c2):
              s = ((s[0:i] + c1) + s[(i + 1):])
      return s
source_cpp: string replace_character_c1_c2_c2_c1_string_s(string s, char c1, char c2) {
    int l = s . length ( );
    for ( int i = 0;
    i < l;
    i ++ ) {
      if ( s [ i ] == c1 ) s [ i ] = c2;
      else if ( s [ i ] == c2 ) s [ i ] = c1;
    }
    return s;
  }