delete pics to save space

history_source/信息学奥赛一本通/1.5.3.6.cpp

@@ -0,0 +1,25 @@
+#include<cstdio>
+#include<cstring>
+bool can(char n)
+{
+	if(n>='a'&&n<='z') return 1;
+	if(n>='A'&&n<='Z') return 1;
+	if(n>='0'&&n<='9') return 1;
+	if(n=='_') return 1;
+	return 0;
+}
+int main()
+{
+    char s[25];
+    gets(s);
+    int len=strlen(s);
+    if(can(s[0]))
+    {
+    	if(s[0]>='0'&&s[0]<='9') goto error;
+    	for(int i=1;i<len;i++)
+    		if(!can(s[i])) goto error;
+    	printf("yes\n");
+    	return 0;
+	}
+	error:{printf("no\n");return 0;}
+}