C++ to achieve hexadecimal string conversion to decimal integer method

This article illustrates the method of converting hexadecimal string into decimal integer in C++. Share with you for your reference. The specific implementation method is as follows:

#include <stdio.h>
#include <math.h>

int hexchtoi(char hexch )
{
 char phexch[] = "ABCDEF";
 char qhexch[] = "abcdef";
 int i;
 for(i=0;i<6;i++){
  if((hexch == phexch[i]) || (hexch == qhexch[i]))
   break;
 }
 printf("i=%d",i);
 if(i >= 6){
  return 0; 
 }
 return 10+i;
}
int htoi(char s[])
{
 int n=0; 
 int valu=1; 
 int i=0,j;
 int answer=0;
 
 if((s[0] == '0') && ((s[1] == 'x') || (s[1] == 'X'))){
  i += 2;
 }
 while((s[i] != 'n')){
  if((s[i] < '0') && (s[i] > '9')){
   if(hexchtoi(s[i]) == 0){
    valu=0;
    break;
   }
  }
  n++;
  i++;
 }
 if(valu != 0){   
  for(j=0;j<n;j++){
   answer += ((int)pow(16,j) * hexchtoi(s[i-j-1]));
  } 
 }
 else
  answer = -1;
 return answer;
}
main()
{
 char *n[] = {"0x7ff0","0x2341"};
 printf("%s is %dn",n[0],htoi(n[0]));
 printf("%s is %dn",n[0],123);
}

Hope that the article described in the C++ programming to help you.