字符串和数字相互转换

1. 十六进制字符串转数字

std::string str = "0xef";char c = (char)strtol(str.c_str(), NULL, 16);printf("0x%02x\n", (unsigned char)c);

结果

2.十六进制数字转字符串

char c = 0x0e;char ch[10] = {0};sprintf(ch, "0x%02x", (unsigned char)c);

结果

3. 十六进制输出字符

char c = 0xa8;printf("0x%02x\n", (unsigned char)c);

结果

此为标准格式：02保证输出长度为两位、不足补0；(unsigned char)