19 lines
422 B
C++
19 lines
422 B
C++
#include<iostream>
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#include<string>
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using namespace std;
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bool pan(string sr)
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{
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if(!((sr[0]>='a'&&sr[0]<='z')||(sr[0]>='A'&&sr[0]<='Z')||sr[0]=='_')) return 0;
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for(int i=0;i<sr.size();i++) if(!((sr[i]>='a'&&sr[i]<='z')||(sr[i]>='A'&&sr[i]<='Z')||sr[i]=='_'||(sr[i]>='0'&&sr[i]<='9'))) return 0;
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return 1;
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}
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int main()
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{
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string sr;
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getline(cin,sr);
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if(pan(sr)) cout<<"yes";
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else cout<<"no";
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cout<<endl;
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return 0;
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}
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