title: Find Position Given Number Among Numbers Made 4 7
signature: function findPositionGivenNumberAmongNumbersMade47(n) {
test_code: 
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  function convertToString(value) {
      return JSON.stringify(value, function (key, val) {
          if (val instanceof Set) {
              return Array.from(val);
          } return val;});
  }
  
  function validateSolution(actual, expected){
      return convertToString(actual)===convertToString(expected);
  }
  
  function driver(n, expected){
      try{
          if (validateSolution(PLACEHOLDER_FN_NAME(n),expected)){
              return "PASSED";
          }
          return "FAILED";
      } catch (error) {
        return error.name;
      }
      
  }
      
  function main(){
    let result = '';
    result = driver("7", 2);
    console.log(`TEST-0...${result}`);
  
    result = driver("305745689", 5);
    console.log(`TEST-1...${result}`);
  
    result = driver("444", 7);
    console.log(`TEST-2...${result}`);
  
    result = driver("4", 1);
    console.log(`TEST-3...${result}`);
  
    result = driver("2074", 5);
    console.log(`TEST-4...${result}`);
  
    result = driver("27", 2);
    console.log(`TEST-5...${result}`);
  
    result = driver("447", 8);
    console.log(`TEST-6...${result}`);
  
    result = driver("255", 0);
    console.log(`TEST-7...${result}`);
  
    result = driver("10000111111011", 0);
    console.log(`TEST-8...${result}`);
  
    result = driver("fAKcSDRTNz", 0);
    console.log(`TEST-9...${result}`);
  
    process.exit(0);
  };
  
  if (require.main === module) {
    main();
  }
source_py: def find_position_given_number_among_numbers_made_4_7(n):
      i = 0
      j = len(n)
      pos = 0
      while (i < j):
          if (n[i] == '4'):
              pos = ((pos * 2) + 1)
          if (n[i] == '7'):
              pos = ((pos * 2) + 2)
          i = (i + 1)
      return pos
source_cpp: int find_position_given_number_among_numbers_made_4_7(string n) {
    int i = 0, pos = 0;
    while ( n [ i ] != '\0' ) {
      switch ( n [ i ] ) {
        case '4' : pos = pos * 2 + 1;
        break;
        case '7' : pos = pos * 2 + 2;
        break;
      }
      i ++;
    }
    return pos;
  }