i find a problem using atoi() method in ansi c?

i have a string initialized by {'\0'} every time i a loop and store some chars in it ranging from 0 to 9 when i convert atoi(temp) where te开发者_StackOverflow中文版mp="2" it returns me 20 instead of 2 what i have to do to get the accurate values, help required.

No matter what your problem with getting atoi to work is, you should rather use strtol. From the libc info manual:

-- Function: int atoi (const char *STRING)

 This function is like `atol', except that it returns an `int'.
 The `atoi' function is also considered obsolete; use `strtol'
 instead

See this answer for example of how to use strtol.

A couple of things to check:

• Have you re-terminated the string, after adding your character(s)?
• Have you allocated enough memory for the whole string, including the new null terminator?

Something like this should work:

char buffer[2] = {'\0'}; // note "[2]" to set aside two bytes
buffer[0] = '2';
buffer[1] = '\0'; // ensure it's still terminated
printf("%d\n", atoi(buffer));

I guess, the problem is not atoi, should be something else. Please check pointers, debug step by step, etc.