distinct char string c++
#include<stdio.h>
#include<string.h>
// function to return the number of unique
// characters in str[]
int count_unique_char(char* str) {
int hash[128] = { 0 };
int i, c = 0;
// reading each character of str[]
for (i = 0; i < strlen(str); ++i) {
// set the position corresponding
// to the ASCII value of str[i] in hash[] to 1
hash[str[i]] = 1;
}
// counting number of unique characters
// repeated elements are only counted once
for (i = 0; i < 128; ++i) {
c += hash[i];
}
return c;
}
int main() {
char str[300];
printf("Enter String: ");
gets(str);
printf("Number of Unique Characters in String: %d", count_unique_char(str));
}