find the frequency of each letter in a string using c programming

We will find the frequency of each letter in a string using c programming. This program will find the occurrence of each character in given string

#include<stdio.h>
#include<conio.h>
#include<string.h>
void main()
{
char str1[10],ch;
int n,i,j;
clrscr();
printf("Enter the String \n");
gets(str1);
for(i=0;str1[i]!='\0';i++)
{
	for(j=0;str1[j]!='\0';j++)
	{
	if(str1[i]==str[j])
	{
	n++;
	}
	}
	printf("%s is found %d times",str[i],n);
}
getch();
}