Identifiers

Time Limit: 1000ms   Memory limit: 65536K  有疑问？点这里^_^

题目描述

 Identifier is an important concept in the C programming language. Identifiers provide names for several language elements, such as functions, variables, labels, etc.

An identifier is a sequence of characters. A valid identifier can contain only upper and lower case alphabetic characters, underscore and digits, and must begin with an alphabetic character or an underscore. Given a list of chararcter sequences, write a program to check if they are valid identifiers.

输入

 The first line of the input contains one integer, N, indicating the number of strings in the input. N lines follow, each of which contains at least one and no more than 100 characters. (only upper and lower case alphabetic characters, digits, underscore (" "), hyphen ("-"), period ("."), comma (","), colon (":"), semicolon (";"), exclamation mark ("!"), question mark ("?"), single and double quotation marks, parentheses, white space and square brackets may appear in the character sequences.)

输出

For each of the N lines, output "Yes" (without quote marks) if the character sequence contained in that line make a valid identifier; output "No" (without quote marks) otherwise.

示例输入

7ValidIdentifiervalid_identifiervalid_identifier0_invalid_identifier1234567invalid identifieradefhklmruvwxyz12356790_-.,:;!?'"()[]ABCDGIJLMQRSTVWXYZ

示例输出

YesYesYesNoNoNoNo

提示

 

来源

山东省第二届ACM大学生程序设计竞赛

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　　水题。

　　代码：

1 #include 
      
        2 #include 
       
         3 using namespace std; 4  5 int main() 6 { 7     int i,j,n; 8     cin>>n; 9     getchar();10     for(i=1;i<=n;i++){11         char a[110];12         cin.getline(a,110,'\n');13         if(('a'<=a[0] && a[0]<='z') || ('A'<=a[0] && a[0]<='Z') || a[0]=='_'){14             for(j=0;a[j];j++)15                 if(!(('a'<=a[j] && a[j]<='z') ||16                      ('A'<=a[j] && a[j]<='Z') ||17                      ('0'<=a[j] && a[j]<='9') ||18                      a[j]=='_') )19                      break;20             if(a[j])21                 cout<<"No"<
       
      

 

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