codeup-100000580 Question B-"Algorithm Notes"

Foreword:

21 Postgraduate entrance examination, I am gnawing "Algorithm Notes", whether I can enter the retest or not to record the garbage code written on the road.

answer:

#include<cstdio>
#define max 105
int main()
{
    
       
	char str[max];
	for(int i=0;i<max;i++)
		str[i]='\0';
	while(gets(str)!=NULL){
    
    
		for(int p=0;str[p]!='\0';p++)
			if(p==0||str[p-1]==' '||str[p-1]=='\t'||str[p-1]=='\r'||str[p-1]=='\n')
			//	对于第一个字符和前一个字符为空白符的字符大写
				printf("%c",str[p]-32);
			else 
				printf("%c",str[p]);
		printf("\n");
		for(int i=0;i<max;i++)
			str[i]='\0';
	}
	return 0;
}

It can only be half right, and I really haven't found out what's wrong.