Identifiers

灰太狼 2022-08-18 02:28 121阅读 0赞

## 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 ##

7
    ValidIdentifier
    valid_identifier
    valid_identifier
    0 invalid identifier
    1234567
    invalid identifier
    adefhklmruvwxyz12356790 -.,:;!?'"()[]ABCDGIJLMQRSTVWXYZ

## 示例输出 ##

Yes
    Yes
    Yes
    No
    No
    No
    No

## 提示 ##

## 来源 ##

山东省第二届ACM大学生程序设计竞赛

## 示例程序 ##

#include<stdio.h>  
    #include<string.h>  
    char a[1000];  
    int main()  
    {  
    int i,j,n,m,k,t;  
    scanf("%d",&n);  
    getchar();  
    for(i=0;i<n;i++)  
    {  
    gets(a);  
    m=strlen(a);  
    k=0;  
    for(j=0;j<m;j++)  
    {  
    if(j==0)  
    {  
    if((a[0]>='a'&&a[0]<='z')||(a[0]>='A'&&a[0]<='Z')||a[0]=='_')  
    continue;  
    else  
    {  
    k=1;  
    break;  
    }  
    }  
    else  
    {  
    if((a[j]>='a'&&a[j]<='z')||(a[j]>='A'&&a[j]<='Z')||(a[j]<='9'&&a[j])>='0'||a[j]=='_')  
    continue;  
    else  
    {  
    k=1;  
    break;  
    }  
    }  
    }  
    //printf("%s\n",a);  
    if(k==1)  
    printf("No\n");  
    else  
    printf("Yes\n");  
    }  
    }