字符转整型，比系统的好用！a2iLxx （涵盖 16进制，VC6亲测可用）请提出宝贵意见~

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#include "string.h"#define INVALID_VALUE_LXX((1 << (8 * sizeof(int) -1)) - 1)/*有符号整型最大值,如果越界将为0, and - is prioty of <<*/#define A2a(ch) (('a' <= (ch) && (ch) <= 'f') ? (ch) : ((ch) - 'A' + 'a'))bool is0to9(char ch){if ('0' <= ch && ch <= '9'){return true;}else{return false;}}bool isatoF(char ch){if (('a' <= ch && ch <= 'f') || ('A' < ch && ch <= 'F')){return true;}else{return false;}}int a2iLxx(char* ch){int index = 0;int retVal = 0;bool flag = false;if (NULL == ch){return INVALID_VALUE_LXX;}/*Ox*/if ('0' == ch[0] && ('x' == ch[1] || 'X' == ch[1])){index = 2;for (; ch[index] != '\0'; index++){/* x * 2^y == x * 1 << y */if (is0to9(ch[index])){retVal = (retVal << 4) + ch[index] - '0';continue;}if (isatoF(ch[index])){retVal = (retVal << 4) + 10 + A2a(ch[index]) - 'a';continue;}return INVALID_VALUE_LXX;}return retVal;}/*10*/index = 0;if ('-' == ch[0]){/*负数*/flag = true;index = 1;}for (; ch[index] != '\0'; index++){if (!is0to9(ch[index])){return INVALID_VALUE_LXX;}retVal = retVal * 10 + ch[index] - '0';}if (flag){return -retVal;}else{return retVal;}}void main(){char ch1[] = "123";char ch2[] = "-234";char ch3[] = "0";char ch4[] = "0x123";char ch5[] = "0xff";int a = INVALID_VALUE_LXX;char d1 = A2a('a');char d2 = A2a('B');/*调试查看值*/a = a2iLxx(ch1);a = a2iLxx(ch2);a = a2iLxx(ch3);a = a2iLxx(ch4);a = a2iLxx(ch5);}

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