Here is a short review of 3 popular “bad” and “good” programming habits.

“Bad” code:

String res = String.Empty;
String app = "ABC";

for (int iCount = 0; iCount < 1000; iCount++)
  res = res + app;

return res;

“Good” code:

String res = String.Empty;
String app = "ABC";

StringBuilder b = new StringBuilder();
for (int iCount = 0; iCount < 1000; iCount++)
  b.Append(app);

return b.ToString();

Result ["bad" vs "good"]:
• Execution time (seconds): 1.63701196660469 vs 0.0429683102181981
• Memory usage (bytes): 3,038,054 vs 33,532

As we can see from the results you should always use StringBuilder class for string manipulation.

“Bad” code:

if (x.ToLower() == "geras")

“Good” code:

if (String.Compare(x, "geras", true) == 0)

Result ["bad" vs "good"]:

• Execution time (seconds): 0.198623009348954 vs 0.136355039537148

• Memory usage (bytes): 19,020 vs 19,596

The increase of “good” code performance is apparent, but it will consume more RAM.

“Bad” code:

int i = 15;

int j = 25;

Console.Write(“{0},{1}”, i, j);

“Good” code:

int i = 15;

int j = 25;

Console.Write("{0},{1}", i.ToString(), j.ToString());

Result ["bad" vs "good"]:

• Execution time (seconds): 0.00588817852548299 vs 0.0114441919294212

• Memory usage (bytes): 25,038 vs 24,934

Even though the “good” code performs not as good as a “bad” code, but it will not require calling “box/unbox” operations, thus uses less memory.