1 files changed, 47 insertions, 0 deletions
diff --git a/Computer_Science/leetcode/65-valid_number.c b/Computer_Science/leetcode/65-valid_number.c
new file mode 100644
index 0000000..b8ee227
--- /dev/null
+++ b/Computer_Science/leetcode/65-valid_number.c
@@ -0,0 +1,47 @@
+#include <string.h>
+
+bool isNumber(char* s) {
+	char *p;
+	int dot_flag = 0;
+	int e_flag = 0;
+
+	for(; *s == ' '; s++)
+		;
+	if(*s == '+' || *s == '-')
+		s++;
+
+	p = s;
+
+	/* trim tail */
+	for(; *p != '\0'; p++)
+		;
+	for(p--; p != s && *p == ' '; p--)
+		;
+	*(p + 1) = '\0';
+
+	p = s;
+	if(*p == '\0') return false;
+	
+	for(; *p != '\0'; p++) {
+		if(*p <= '9' && *p >= '0')
+			continue;
+		else if(*p == '.') {
+			if(dot_flag == 1)
+				return false;
+			if((s == p && *(p + 1) == '\0')
+			   || *(p - 1) == 'e')
+				return false;
+			dot_flag = 1;
+			continue;
+		} else if(*p == 'e') {
+			if(e_flag == 1)
+				return false;
+			if(s == p || *(p + 1) == '\0' || (*(p - 1) == '.' && p - 1 == s))
+				return false;
+			e_flag = 1;
+		} else
+			return false;
+	}
+
+	return true;
+}