Distinct Characters

C program to find number of distinct characters in a string.

#include<stdio.h>
int main()
{
char a[100001];

unsigned int b[26],i=0,c=0;

memset(b,0,26*sizeof(unsigned int));

printf("Enter the String: ");

scanf("%s",a);

while(a[i]!='\0')

{

b[a[i]-'a']++;

i++;

}

for(i=0;i<26;i++)

{

if(b[i]!=0) c++;

}

printf("There are total %u characters in string.\n",c);

return 0;

}