add: str_replace

src/str/str.h

@@ -10,3 +10,4 @@ void str_shift(char *str, int shift);
 int str_contain_only(const char *str, const char *charset);
 char* str_merger(size_t arg_len, ...);
 char* str_join(const char* s1, const char* s2);
+char* str_replace(const char *str, const char *fill, size_t start, size_t stop);

src/str/str_replace.c

@@ -0,0 +1,19 @@
+#include "./str.h"
+
+char	*str_replace(const char *str, const char *fill, size_t start, size_t stop)
+{
+	char	*out;
+	size_t	sum;
+
+	out = malloc((strlen(str) + strlen(fill) -\
+				(stop - start) + 1 * sizeof(char)));
+	if (out == NULL)
+		return (NULL);
+	strncpy(out, str, start);
+	strncpy(out + start, fill, strlen(fill));
+	sum = start + strlen(fill);
+	strncpy(out + sum, str + stop, strlen(str) - stop);
+	out[sum + strlen(str) - stop] = '\0';
+	return (out);
+}
+