1 files changed, 113 insertions, 0 deletions
diff --git a/ft_strnstr.c b/ft_strnstr.c
new file mode 100644
index 0000000..f7042d6
--- /dev/null
+++ b/ft_strnstr.c
@@ -0,0 +1,113 @@
+/*
+Libft Copyright (C) 2026 yctct
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include "libft.h"
+
+char	*ft_strnstr(const char *big, const char *little, size_t len)
+{
+	unsigned long	i;
+	int				j;
+
+	if (ft_strlen(little) <= 0)
+		return ((char *)(big));
+	i = 0;
+	while (big[i] != '\0' && i < len)
+	{
+		if (big[i] == little[0])
+		{
+			j = 0;
+			while (big[i + j] == little[j] && little[j] && (i + j) < len)
+				j++;
+			if (little[j] == '\0')
+				return ((char *)(&big[i]));
+		}
+		i++;
+	}
+	return (NULL);
+}
+/*
+#include <bsd/string.h>
+#include <stdio.h>
+#include <string.h>
+
+int	main(void)
+{
+		const char *largestring = "Foo Bar Caz";
+		const char *smallstring = "Bar";
+		const char *empty_smallstring = "";
+		const char *largestring2 = "Foo Baz Caz";
+		const char *smallstring2 = "Bar";
+		const char *largestring3 = "Foo Bar Baz";
+		const char *smallstring3 = "Baz";
+
+	printf("  the big string is: %s\n", largestring);
+	printf("the small string is: %s\n", smallstring);
+		printf("            strnstr: %s\n",
+strnstr(largestring, smallstring, 7));
+		printf("         ft_strnstr: %s\n",
+ft_strnstr(largestring, smallstring, 7));
+	printf("----------------------------------
+---------------------------------\n");
+	printf("When the small string is empty,
+ the function returns the big string\n");
+	printf("  the big string is: %s\n", largestring);
+	printf("the small string is: %s\n", empty_smallstring);
+		printf("            strnstr: %s\n",
+strnstr(largestring, empty_smallstring, 7));
+		printf("         ft_strnstr: %s\n",
+ft_strnstr(largestring, empty_smallstring, 7));
+	printf("------------------------------
+-------------------------------------\n");
+	printf("When the little string occurs
+nowhere in big, NULL is returned\n");
+	printf("  the big string is: %s\n", largestring2);
+	printf("the small string is: %s\n", smallstring2);
+		printf("            strnstr: %s\n",
+strnstr(largestring2, smallstring2, 7));
+		printf("         ft_strnstr: %s\n",
+ft_strnstr(largestring2, smallstring2, 7));
+	printf("-------------------------------
+------------------------------------\n");
+	printf("When the little string occurs
+at the end of big\n");
+	printf("  the big string is: %s\n", largestring3);
+	printf("the small string is: %s\n", smallstring3);
+		printf("            strnstr: %s\n",
+strnstr(largestring3, smallstring3, 11));
+		printf("         ft_strnstr: %s\n",
+ft_strnstr(largestring3, smallstring3, 11));
+	printf("-----------------------------------
+--------------------------------\n");
+	printf("When length is smaller than
+necessary to print little\n");
+	printf("  the big string is: %s\n", largestring3);
+	printf("the small string is: %s\n", smallstring3);
+		printf("            strnstr: %s\n",
+strnstr(largestring3, smallstring3, 10));
+		printf("         ft_strnstr: %s\n",
+ft_strnstr(largestring3, smallstring3, 10));
+	printf("----------------------------
+---------------------------------------\n");
+	printf("When length is zero\n");
+	printf("  the big string is: %s\n", largestring3);
+	printf("the small string is: %s\n", smallstring3);
+		printf("            strnstr: %s\n",
+strnstr(largestring3, smallstring3, 0));
+		printf("         ft_strnstr: %s\n",
+ft_strnstr(largestring3, smallstring3, 0));
+}
+*/