title: Replace Character C1 C2 C2 C1 String S
signature: function replaceCharacterC1C2C2C1StringS($s, $c1, $c2) {
test_code: <?php
  
  
  // SOLUTION CODE 
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  function validateSolution($actual, $expected){
      return serialize($actual) == serialize($expected);
  }
  
  function driver($s, $c1, $c2, $expected){
      try{
        if (validateSolution(PLACEHOLDER_FN_NAME($s, $c1, $c2), $expected)){
          return "PASSED";
        }
        return "FAILED";
      }
      catch (Exception $exception_obj) {
        return get_class($exception_obj);
      }
  }
  
  function main(){
      printf("TEST-0...%s\n",driver(
        "IZTSMw j", 'W', 'k', 
        "IZTSMw j"));
      
      printf("TEST-1...%s\n",driver(
        "7288334", '6', '9', 
        "7288334"));
      
      printf("TEST-2...%s\n",driver(
        "010110000", '1', '1', 
        "010110000"));
      
      printf("TEST-3...%s\n",driver(
        "b gJX", 't', 'P', 
        "b gJX"));
      
      printf("TEST-4...%s\n",driver(
        "734", '4', '4', 
        "734"));
      
      printf("TEST-5...%s\n",driver(
        "1", '1', '1', 
        "1"));
      
      printf("TEST-6...%s\n",driver(
        "xCaUKdhA", 'X', 'S', 
        "xCaUKdhA"));
      
      printf("TEST-7...%s\n",driver(
        "4370992644981", '5', '6', 
        "4370992544981"));
      
      printf("TEST-8...%s\n",driver(
        "01010", '0', '1', 
        "10101"));
      
      printf("TEST-9...%s\n",driver(
        "ZNIFGshaWA", 'Q', 'x', 
        "ZNIFGshaWA"));
      
  }
  
  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;
  }