问莱克斯:将十六进制转换为12月

EN

{hex} {count++;printf("%d\t(hex,%d)\n",count,hextodec(yytext));}
{oct} {count++;printf("%d\t(oct,%d)\n",count,octtodec(atoi(yytext)));}



int octtodec(int oct){
 int dec=0,pos=0;
 while (oct){
     int a=oct%10;
     dec += a * pow(8,pos);
     pos++;
     oct /= 10;
 }
 return dec;}

 int hextodec(char *hex){
 int dec=0,pos=0;
 int len;
 len=strlen(hex);
 for (int i =2;i<len;i++){
     if(hex[i]>='a'&&hex[i]<='f'){
         dec=dec+(hex[i]-'a'+10)*pow(16,len-i-1);
     }
     else if(hex[i]>='A'&&hex[i]<='F'){
         dec=dec+(hex[i]-'A'+10)*pow(16,len-i-1);
     }
     else{
         dec+=(hex[i]-'0')*pow(16,len-i-1);
     }
 }
 return dec;}