Initial commit: libft Part 1 with tests and documentation

Reimplements 24 libc functions with Doxygen-documented header
and test suite comparing against libc.

1 files changed, 26 insertions, 0 deletions

diff --git a/ft_atoi.c b/ft_atoi.c
new file mode 100644
index 0000000..2fe091a
--- /dev/null
+++ b/ft_atoi.c
@@ -0,0 +1,26 @@
+#include "libft.h"
+
+int
+ft_atoi (const char *nptr)
+{
+  int sign;
+  int result;
+
+  result = 0;
+  sign = 1;
+  // Skip isspace() characters: space, \t, \n, \v, \f, \r.
+  while (*nptr == ' ' || (*nptr >= '\t' && *nptr <= '\r'))
+    nptr++;
+  if (*nptr == '-' || *nptr == '+')
+    {
+      if (*nptr == '-')
+        sign = -1;
+      nptr++;
+    }
+  while (*nptr >= '0' && *nptr <= '9')
+    {
+      result = result * 10 + (*nptr - '0');
+      nptr++;
+    }
+  return (result * sign);
+}