TryCatch.sol

pragma solidity ^0.6.0;

interface DataFeed { function getData(address token) external returns (uint value); }

contract FeedConsumer {
  DataFeed feed;
      uint errorCount;
     function rate(address token) public returns (uint value, bool success) {
        // Permanently disable the mechanism if there are
        // more than 10 errors.
        require(errorCount < 10);
        try    feed.getData(token)
        returns (uint v)    {
              return (v, true);
        } catch 
        Error(string memory /*reason*/) 
          {
            // This is executed in case
            // revert was called inside getData
            // and a reason string was provided.
            errorCount++;
            return (0, false);
        }      catch (bytes memory /*lowLevelData*/
                     ) {
            // This is executed in case revert() was used
            // or there was a failing assertion, division
            // by zero, etc. inside getData.
          errorCount++;
          return (0, false);
        } }

        function rate2(address token) public returns (uint value, bool success) {
           // Permanently disable the mechanism if there are
           // more than 10 errors.
           require(errorCount < 10);
           try    feed.getData(token)
           returns (uint v, uint v1,uint v2,uint v3,uint v4,uint v5,uint v6,uint v7,uint v8)    {
                 return (v, true);
           } catch
           Error(string memory /*reason*/)
             {
               // This is executed in case
               // revert was called inside getData
               // and a reason string was provided.
               errorCount++;
               return (0, false);
           }      catch (bytes memory /*lowLevelData*/
                        ) {
               // This is executed in case revert() was used
               // or there was a failing assertion, division
               // by zero, etc. inside getData.
             errorCount++;
             return (0, false);
           } }

           function rate3(address token) public returns (uint value, bool success) {
              // Permanently disable the mechanism if there are
              // more than 10 errors.
              require(errorCount < 10);
              try    feed.getData(token)   {
                    return (v, true);
              } catch
              Error(string memory /*reason*/)
                {
                  // This is executed in case
                  // revert was called inside getData
                  // and a reason string was provided.
                  errorCount++;
                  return (0, false);
              }      catch {
                  // This is executed in case revert() was used
                  // or there was a failing assertion, division
                  // by zero, etc. inside getData.
                errorCount++;
                return (0, false);
              } }

    function rate4(address token) public returns (uint value, bool success) {
        // Permanently disable the mechanism if there are
        // more than 10 errors.
        require(errorCount < 10);
        try feed.getData(token) returns (uint v) {
            return (v, true);
        } catch Error(string memory /*reason*/) {
            // This is executed in case
            // revert was called inside getData
            // and a reason string was provided.
            errorCount++;
            return (0, false);
        } catch Panic(uint /*errorCode*/) {
            // This is executed in case of a panic,
            // i.e. a serious error like division by zero
            // or overflow. The error code can be used
            // to determine the kind of error.
            errorCount++;
            return (0, false);
        } catch (bytes memory /*lowLevelData*/) {
            // This is executed in case revert() was used.
            errorCount++;
            return (0, false);
        }
    }
}

contract Test {
    function getAdjustedBalance(IERC20 token) internal view returns (uint256) {
        uint256 balance;

        try token.balanceOf(address(this)) returns (uint256 result) {
            balance = result;
        } catch {
            return 0;
        }

        return balance - 100;
    }
}