10进制/16进制字符串和数字转换

#include <stdio.h>
#include <stdlib.h>

int main()
{
  //1.将10进制和16进制字符串转换成数字
  char a[] = "100";
  char c[] = "0xff";
  printf("a = %ld\n", strtol(a, NULL, 10)); //100
  printf("c = %ld\n", strtol(c, NULL, 16)); //255

  //2.将数字转换成16进制字符串
  int rreg = 9;
  char reg[16] = {0};
  char cmd[64] = {0};

  sprintf(reg,"0x%02x", rreg);//02x:如果小于9则补0；大于9则实际输出;2x则是实际输出(不补0)
  sprintf(cmd,"echo \"%s\" > /dev/led", reg);
  printf("cmd = %s\n",cmd);
  return 0;
}