NAME

atof - convert a string to a float

atof - convert a string to a double

LIBRARY

Standard C library (libc, -lc)

#include <stdlib.h>

float atof(string s);

#include <stdlib.h>
double atof(const char *nptr);

This function converts a (positive or negative) floating-point value from a string (e.g., "50.0") to a float (e.g., 50.0).

The atof() function converts the initial portion of the string pointed to by nptr to double. The behavior is the same as

strtod(nptr, NULL);

except that atof() does not detect errors.

This function returns its input, s, as a float.

The converted value.

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    printf("This is CS%.0f\n", atof("50.0"));
}

For an explanation of the terms used in this section, see attributes(7).

Interface	Attribute	Value
atof()	Thread safety	MT-Safe locale

C11, POSIX.1-2008.

POSIX.1-2001, C89, C99, SVr4, 4.3BSD.