自我实现itoa(整形转字符串)

自我实现itoa(整形转字符串)

如： 123 转换成 “123”

“-123” 转换成 -123

#include <stdio.h>

int IntegerToString(int num, char *str)
{
if (str == NULL)
{
return -1;
}

int temp = num; //先定义临时变量记录num
int len = 0;   //num  的位数
int count = 0;
int flag = 1;

if (num < 0)
{
flag = -1;   //负数则放置标志-1，并先转化为正数处理
num *= -1;
}

while (temp)
{
temp /= 10;
len++;   //num的位数
}

count = len;

while (num)
{
str[--len] = num % 10 + '0'; //将各位数转为字符串放在数组里
num /= 10;
}
str[count] = '\0';

if (flag == -1) //处理负数
{
while (count >= 0)
{
str[count + 1] = str[count]; //将数组整体后移1位
count--;
}
str[0] = '-';   //将'-'插入到开头
}
}

int main()
{
int num = 0;
char str[100] = {0}; //用于存放处理好的字符串

printf ("please input a integer: ");
scanf ("%d", &num);
printf ("The original number is %d\n", num);

if ( IntegerToString(num, str) == -1 )
{
printf ("function IntegerToString error!\n");
return -1;
}

printf ("The result is %s\n", str);

return 0;
}