C语言:从两端滚动输出

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#include<stdio.h>
#include<string.h>
#include<windows.h>
#include<stdlib.h>
int main()
{
	char arr1[] = "happy every day!!!";
	char arr2[] = "                  ";
	int left = 0;
	int right = strlen(arr1) - 1;
	while (left <= right)
	{
		arr2[left] = arr1[left];
		arr2[right] = arr1[right];
		left++;
		right--;
		Sleep(300);
		system("cls");
		printf("%s", arr2);
	}
	return 0;
}