整数转化成字符串，字符串转化成整数

//整数转化成字符串
#include <iostream>
#include <stdio.h>


int main(void)
{
int num = 12345, j = 0, i = 0;
char temp[7], str[7];


//itoa(number, string, 10);


while(num)
{
temp[i] = num % 10 + '0';
i++;
num = num / 10;
}
temp[i] = 0;
printf(" temp = %s\n", temp);
i = i - 1;
printf(" temp = %d\n", i);
//刚刚转化的字符串是逆序的，必须把它反转过来
while(i >= 0)
{
str[j] = temp[i];
j++;
i--;
}
str[j] = 0;
printf(" string = %s\n", str);
return 0;
}


//字符串转化成整数
int main(void)
{
int num = 12345, j = 0, i = 0, sum = 0;
char temp[7] = {'1', '2', '3', '4', '5', '\0'}, str[7];
while(temp[i])
{
sum = sum * 10 + (temp[i] - '0');
i++;
}
printf(" sum = %d\n", sum);
return 0;
}