int atoi(const char *str
The string pointed to by the argument str is converted to
an integer (type
int). Any initial
whitespace characters are skipped (space, tab, carriage return,
new line, vertical tab, or formfeed). The number may consist of
an optional sign and a string of digits. Conversion stops when
the first unrecognized character is reached.
On success the converted number is returned. If the number
cannot be converted, then
0 is returned.