Thread: Determining number of times a character appears in an array

Below is my program. It works but then it gives a run time check failure- stack around the variable 'str2' was corrupted. I have no idea what the deal is. Thanks

Code:

#include <stdio.h>
#include <string.h>
int main (void)
{
	int k = 0;
	int count = 0;
	int n;
	char *pt;
	char *pt2;
	char str[256];
	char str2[1];
	printf("Enter sentence. \n");
	while((str[k]=getchar()) != '\n')
		k++;
	str[k]='\0';
	n= k + 1;
	pt=str;
	printf("Enter character to find in sentence. \n");
	scanf("%s", str2);
	pt2=str2;

	while((pt=strstr(pt, pt2)) != NULL)
	{
		count++;
		pt++;
	}
	printf("Number of times %s occurs: %d \n",str2, count);
	
return 0;
}