关于十六进制转化成十进制的问题

# include <stdio.h>
# define N 100
char htoi(char s[]);
int main()
{
char a[N];
printf(“请输入十六进制数的字符串”);
gets(a);
htoi(a);
printf(“十进制数为：%d”, htoi(a));
return 0;
}
char htoi(char s[])
{
int i;
int n;
int sum;
sum = 0;
for (i = 0; s[i] != “”\0″”; i++)
{
if (s[i] >= “”0″” || s[i] <= “”9″”)
n = s[i] – “”0″”;
if (s[i] >= “”a”” || s[i] <= “”z””)
n = s[i] – 87;
if (s[i] >= “”A”” || s[i] <= “”Z””)
n = s[i] – 55;
sum = 16 * sum + n;
}
return sum;
}
帮本人看一下本人这代码错哪了，改代码是为了实现将十六进制数转化成十进制，0x为开头的十六进制数也可实现

仅供参考：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <locale.h>
int main() {
    int i,v;
    char bs[33];
    char b[33];
    char hs[9];
    char h[9];
    char s[4];
    char *e;
// 十进制整数转二进制串；
    i=1024;
    ltoa(i,b,2);
    sprintf(bs,"%032s",b);
    printf("i=%d,bs=%s\n",i,bs);
// 十进制整数转十六进制串；
    i=1024;
    ltoa(i,h,16);
    sprintf(hs,"%08s",h);
    printf("i=%d,hs=%s\n",i,hs);
// 十六进制字符串转成十进制数
    strcpy(hs,"00000400");
    sscanf(hs,"%x",&i);
    printf("hs=%s,i=%d\n",hs,i);
// 二进制字符串转化为十六进制字符串；
    strcpy(bs,"00000000000000000000010000000000");
    i=strtol(bs,&e,2);
    ltoa(i,h,16);
    sprintf(hs,"%08s",h);
    printf("bs=%s,hs=%s\n",bs,hs);
// 二进制字符串转化为十进制数；
    strcpy(bs,"00000000000000000000010000000000");
    i=strtol(bs,&e,2);
    printf("bs=%s,i=%d\n",bs,i);
// 十六进制字符串转成二进制串
    strcpy(hs,"00000400");
    sscanf(hs,"%x",&i);
    ltoa(i,b,2);
    sprintf(bs,"%032s",b);
    printf("hs=%s,bs=%s\n",hs,bs);
// ASC\GBK字符串转十六进制串
    strcpy(s,"a汉");
    i=0;
    while (1) {
        if (0==s[i]) break;
        sprintf(hs+i*2,"%02X",(unsigned char)s[i]);
        i++;
    }
    setlocale(LC_ALL,"chs");
    printf("s=%s,hs=%s\n",s,hs);
// 十六进制字符串转成汉字（GBK）及字符(ASC)
    strcpy(hs,"61BABA");
    i=0;
    while (1) {
        if (1!=sscanf(hs+i*2,"%2x",&v)) break;
        s[i]=(char)v;
        i++;
    }
    s[i]=0;
    printf("hs=%s,s=%s\n",hs,s);
    return 0;
}
//i=1024,bs=00000000000000000000010000000000
//i=1024,hs=00000400
//hs=00000400,i=1024
//bs=00000000000000000000010000000000,hs=00000400
//bs=00000000000000000000010000000000,i=1024
//hs=00000400,bs=00000000000000000000010000000000
//s=a汉,hs=61BABA
//hs=61BABA,s=a汉

if (s[i] >= “”0″” || s[i] <= “”9″”)
应该是用&&而不是 || 吧，其他几个if中的也对应改了

另外，htoi的返回值应该是int不是char吧

# include <stdio.h>
# define N 100
int htoi(char s[]);
int main()
{
	char a[N];
	printf("请输入十六进制数的字符串");
	gets(a);
	htoi(a);
	printf("十进制数为：%d", htoi(a));
	return 0;
}
int htoi(char s[])
{
	int i;
	int n;
	int sum;
	sum = 0;
	for (i = 0; s[i] != ""\0""; i++)
	{
		if (s[i] >= ""0"" && s[i] <= ""9"")
			n = s[i] - ""0"";
		else if (s[i] >= ""a"" && s[i] <= ""z"")
			n = s[i] - 87;
		else if (s[i] >= ""A"" && s[i] <= ""Z"")
			n = s[i] - 55;
		sum = 16 * sum + n;
	}
	return sum;
}