还有为什么不给c一开始赋值的话就只输出End? 感谢

#include <stdio.h>
int main()
{
    long long a,c=0;
    scanf("%lld",&a);
    while(c!=1){
    	if(a%2!=0){
    		c=a*3+1;
    		printf("%lld*3+1=%lld\n",a,c);
    		a=c;
		}
		else{
		c=a/2;
		printf("%lld/2=%lld\n",a,c);
		a=c;	
		}
	}
	printf("End");
	return 0;
}