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ft_atoi.c
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ft_atoi.c
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/* ************************************************************************** */
/* */
/* :::::::: */
/* ft_atoi.c :+: :+: */
/* +:+ */
/* By: dreijans <[email protected]> +#+ */
/* +#+ */
/* Created: 2022/10/14 09:41:41 by dreijans #+# #+# */
/* Updated: 2023/05/02 19:36:00 by dreijans ######## odam.nl */
/* */
/* ************************************************************************** */
#include "libft.h"
static int ft_iswhitespace(char c)
{
return (c == ' ' || ((c >= 9 && c <= 13)));
}
long int ft_atoi(const char *str)
{
long i;
long sign;
long number;
number = 0;
sign = 1;
i = 0;
while (ft_iswhitespace(str[i]) && str[i] != '\0')
{
i++;
}
if (str[i] == '+' || str[i] == '-')
{
if (str[i] == '-')
sign = sign * -1;
i++;
}
while (ft_isdigit(str[i]))
{
number = number * 10 + str[i] -48;
i++;
}
return (number * sign);
}
/*
1)does not recognize or +/- decimal points,
2)ignores whitespace
3)skip white space characters
4)detect minus
by doing the conversion you subtract 48 from
your char value of a number getting the actual int
CHECK WHITE SPACE check !!!!!!!man isspace!!!!
let op dat je niet int met char vergelijkt
en denkt dat het werkt! i != '\0' is niet hetzelfde als str[i] != '\0'
2147483647 + 1 = -2147483648
*/