Frequency of Characters

Write a program to find the frequency of characters in a string(case insensitivity)

C    PYTHON

#include<stdio.h>
int main() {
  char str[100];
  int i, j, k, count;
  gets(str);
  for(i=0;str[i+1]!='\0';i++){
    count = 1;
    for(j=i+1;str[j]!='\0';j++){
      if(str[i]==str[j] || str[i]==str[j]+32 || str[i]==str[j]-32){
        count++;
        for(k=j;str[k]!='\0';k++)
          str[k] = str[k+1];
      }
    }
    printf("%c - %d\n",str[i],count);
  }
  return 0;
}

string = input()
freq = {}
for i in range(len(string)-1):
  c=1
  for j in range(i+1,len(string)):
    if string[i]==string[j] or string[i]==chr(ord(string[j])+32) or string[i]==chr(ord(string[j])-32):
      c+=1
  if string[i] in freq:
    freq[string[i]] += 1
  elif chr(ord(string[i])+32) in freq:
    freq[chr(ord(string[i])+32)] += 1
  elif chr(ord(string[j])-32) in freq:
    freq[chr(ord(string[j])-32)] += 1
  else:
    freq[string[i]] = 1
for k,v in freq.items():
  print(k,"-",v)

helloHowarEyou?
h - 2
e - 2
l - 2
o - 3
w - 1
a - 1
r - 1
y - 1
u - 1
? - 1