#include <stdio.h>

#include <math.h>

void hexto(char hex[]){
    unsigned int res = 0;
    for(int i = 0; hex[i]!='\0'; i++){
        if(hex[i] >= 'a' && hex[i] <= 'f'){
            res = res*16 + hex[i]-'a'+10;
        }else if(hex[i] >= 'A' && hex[i] <= 'F'){
            res = res*16 + hex[i]-'A'+10;
        }else{
            res = res*16 + hex[i]-'0';
        }
    }
    printf("十六进制书%s=>十进制数%u",hex,res);
}

int main(){
   char hex[8];
   printf("请输入一个16进制数\n");
   scanf("%s",hex);
   hexto(hex);
}