用C语言输出回文序列

给定一个数字, 请构造它的回文数字.
例如给定1234, 输出1234321, 给定1357输出1357531
int main()

int main()
{
int num, arr[20];
int count = 0;
printf("请输入一个整数:");
scanf("%d", &num);
int temp = num;
while (temp > 0) {
arr[count] = temp % 10;
count++;
temp /= 10;

}
printf("构造的回文数:");
printf("%d", num);
for (int i = 1;i <= count-1;i++)
{
printf("%d", arr[i]);
}
printf("\n");
return 0;

}