電文密碼

#include <stdio.h>
/*電文密碼
A->Z
B->Y
C->X
...*/
int main()
{
	char a[20];
	char c;
	int i;
	gets_s(a, 20);
	for (i = 0; (c = a[i]) != '\0'; i++)
	{
		if (a[i] <= 90 && a[i] >= 65)
			a[i] = 90 - c + 65;
		if (a[i] >= 97 && a[i] <= 122)
			a[i] = 122 - c + 97;
	}

	printf("%s", a);
	return 0;

}