C identifiers

小咪咪 2022-08-18 02:26 98阅读 0赞

## C identifiers ##

####  ####

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

## 题目描述 ##

Identifiers is an important concept in the C programming language,so it is very necessary for every acmer to be clear about the concept.Identifiers provide names for several language elements,such as functions,variables, labels,etc.

An identifier is a sequence of characters.A valid identifiers 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 character sequences,your task is to judge whether they are valid identifiers.

## 输入 ##

The first line of the input contains one integer T ( 0 < T ≤ 100) ,indicating the number of strings in the input.T 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 T 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
    ACM_2011
    _ACM_SDUT_2011
    0_sum
    SUM2000--2011
    Invalid identifier
    Abcde0123_--,;!?"()'::[ACM]

## 示例输出 ##

Yes
    Yes
    Yes
    No
    No
    No
    No

## 提示 ##

## 来源 ##

## 示例程序 ##

#include<stdio.h>  
    #include<string.h>  
    int main()  
    {  
        char a[200];  
        int i,j,n,m,k,t;  
        scanf("%d",&n);  
        getchar();  
        while(n--)  
        {  
            gets(a);  
            m=strlen(a);  
            j=0;  
            for(i=0;i<m;i++)  
            {  
                if(i==0)  
                {  
      
                    if((a[i]>='a'&&a[i]<='z')||(a[i]>='A'&&a[i]<='Z')||a[i]=='_')  
                        continue;  
                    else  
                    {  
                       j=1;  
                       break;  
                    }  
                }  
                else  
                {  
                    if((a[i]>='a'&&a[i]<='z')||(a[i]>='A'&&a[i]<='Z')||(a[i]>='0'&&a[i]<='9')||a[i]=='_')  
                        continue;  
                    else  
                    {  
                        j=1;  
                        break;  
                    }  
                }  
            }  
            if(j==1)  
                printf("No\n");  
            else  
                printf("Yes\n");  
        }  
    }