#include <math.h> #include <stdlib.h>.. double x; x=atof("3.1425936"); int y; y=atoi("25");
Convert strings to double (atof), integer (atoi, _atoi64), or long (atol).Example/* ATOF.C: This program shows how numbers stored * as strings can be converted to numeric values * using the atof, atoi, and atol functions. */#include <stdlib.h> #include <stdio.h>void main( void ) { char *s; double x; int i; long l; s = " -2309.12E-15"; /* Test of atof */ x = atof( s ); printf( "atof test: ASCII string: %s\tfloat: %e\n", s, x ); s = "7.8912654773d210"; /* Test of atof */ x = atof( s ); printf( "atof test: ASCII string: %s\tfloat: %e\n", s, x ); s = " -9885 pigs"; /* Test of atoi */ i = atoi( s ); printf( "atoi test: ASCII string: %s\t\tinteger: %d\n", s, i ); s = "98854 dollars"; /* Test of atol */ l = atol( s ); printf( "atol test: ASCII string: %s\t\tlong: %ld\n", s, l ); } Outputatof test: ASCII string: -2309.12E-15 float: -2.309120e-012 atof test: ASCII string: 7.8912654773d210 float: 7.891265e+210 atoi test: ASCII string: -9885 pigs integer: -9885 atol test: ASCII string: 98854 dollars long: 98854
#include <stdlib.h>..
double x;
x=atof("3.1425936");
int y;
y=atoi("25");
* as strings can be converted to numeric values
* using the atof, atoi, and atol functions.
*/#include <stdlib.h>
#include <stdio.h>void main( void )
{
char *s; double x; int i; long l; s = " -2309.12E-15"; /* Test of atof */
x = atof( s );
printf( "atof test: ASCII string: %s\tfloat: %e\n", s, x ); s = "7.8912654773d210"; /* Test of atof */
x = atof( s );
printf( "atof test: ASCII string: %s\tfloat: %e\n", s, x ); s = " -9885 pigs"; /* Test of atoi */
i = atoi( s );
printf( "atoi test: ASCII string: %s\t\tinteger: %d\n", s, i ); s = "98854 dollars"; /* Test of atol */
l = atol( s );
printf( "atol test: ASCII string: %s\t\tlong: %ld\n", s, l );
}
Outputatof test: ASCII string: -2309.12E-15 float: -2.309120e-012
atof test: ASCII string: 7.8912654773d210 float: 7.891265e+210
atoi test: ASCII string: -9885 pigs integer: -9885
atol test: ASCII string: 98854 dollars long: 98854