C程序--输出大写英文字母

参考博文 https://blog.csdn.net/qq_43332389/article/details/84099175

#include <stdio.h>
#define N 80
int main()
{
	char s1[N],s2[N] = {0};
	int i,j,k=0;
	int flag=0;
	gets(s1);
	for(i=0;s1[i]!='\0';i++)
	{
		if(s1[i]>='A'&&s1[i]<='Z')
		{
			flag=1;
			for(j=0;j<k;j++)
			if(s1[i]==s2[j])
			break;
			if(j>=k)
			{
				s2[k]=s1[i];
				k++;
			}
		}
	}
	if(flag==0)
	printf("Not Found");
	else
	puts(s2);
	return 0;
}