o_195h4n6al16jb186b1b2qs7fgssa.pdf

Language Tools Libraries
DS51456B-page 274 2004 Microchip Technology Inc.
atof
Description: Converts a string to a double precision floating-point value.
Include:
Prototype: double atof(const char *s);
Argument: s pointer to the string to be converted
Return Value: Returns the converted value if successful; otherwise, returns 0.
Remarks: The number may consist of the following:
[whitespace] [sign] digits [.digits]
[ { e | E }[sign]digits]
optional whitespace, followed by an optional signthen a sequence
of one or more digitswith an optional decimal point, followed by one
or more optional digitsand an optional eor Efollowed by an optional
signed exponent. The conversion stops when the first unrecognized
character is reached. The conversion is the same as strtod(s,0,0)
except it does no error checking so errnowill not be set.
Example: #include /* for printf */
#include /* for atof */
int main(void)
{
char a[] = " 1.28";
char b[] = "27.835e2";
char c[] = "Number1";
double x;
x = atof(a);
printf("String = \"%s\" float = %f\n", a, x);
x = atof(b);
printf("String = \"%s\" float = %f\n", b, x);
x = atof(c);
printf("String = \"%s\" float = %f\n", c, x);
}
Output:
String = "1.28" float = 1.280000
String = "27.835:e2"float = 2783.500000
String = "Number1" float = 0.000000
Standard C Libraries with Math Functions
2004 Microchip Technology Inc. DS51456B-page 275
atoi
qsort (danh sách, NUM, sizeof (int), comp);
printf ("Sắp xếp liệt kê:");
for (x = 0; x