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