C语言程序：将十六进制字符串转换为十进制整数

#include<stdio.h>

int hexvalue(char str[]);

int main() { char s[80]; printf("Enter a string(hex):"); scanf("%s", s); printf("%sH=%dD\n", s, hexvalue(s));

}

int hexvalue(char str[]) { int n, i, data = 0; for(i = 0; str[i] != '\0'; i++) { if(str[i] >= '0' && str[i] <= '9') n = str[i] - '0'; else if(str[i] >= 'A' && str[i] <= 'F') n = str[i] - 'A' + 10; else if(str[i] >= 'a' && str[i] <= 'f') n = str[i] - 'a' + 10; else break; data = data * 16 + n; } return data; }