counting of different characters is done by using strlen(i.e string length) and arr denotes array. We use for loop to pass the ASCII code of alphabets from a to z.

   #include<stdio.h>
    #include<string.h>
    void main()
    {
        char arr[]="askjdfbajksdfkasdfhjkasdfh";
        char x;
        int l=strlen(arr);
        int i=0,j;
        int c=0,var=0;
        for(j=97;j<=122;j++)      //a=97,z=122
        {   
            //c=j;
            for(i=0;i<l-1;i++)
            {
                if(arr[i]==j)
                {
                    c++;
                }   
            }
            //cout<<"No. of Occurence of "<<c<<"::"<<c; 
                if(c>0)
                {   
                                   var++;
                    printf("No. of Occurence of %c ::%d\n",j,c);
                }   

            c=0;
        }
    printf("No. of type of characters:%d\n",var);

    }