PE 04.01.20 Q6

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

/* Tra ve index tim thay cua c trong mang arr[]
   Neu khong thay: tra ve -1 */
int indexOf(char c, char arr[], int size) {
    int i;

    for (i = 0; i < size; i++) {
        if (arr[i] == c) {
            return i;
        }
    }
    return -1;
}

int main() {
  system("cls");
  //INPUT - @STUDENT:ADD YOUR CODE FOR INPUT HERE:
    char s[51];
    gets(s);
  // Fixed Do not edit anything here.
  printf("\nOUTPUT:\n");
  //@STUDENT: WRITE YOUR OUTPUT HERE:
    char characters[51];
    int count[51];
    int i, size = 0, index;

    for(i = 0; i < strlen(s); i++) {
        if (s[i] >= 97 && s[i] <= 122) { // a-z
            /* check xem co trong mang characters hay chua?
               neu co roi: tang count 1
               neu chua co: them vao mang characters */
            index = indexOf(s[i], characters, size);
            if (index != -1) { // tim thay ~> tang count 1
                count[index]++;
            } else {
                characters[size] = s[i];
                count[size] = 1;
                size++;
            }
        }
    }

    printf("%c_%d", characters[0], count[0]);
    for(i = 1; i < size; i++) {
        printf(" %c_%d", characters[i], count[i]);
    }
  //--FIXED PART - DO NOT EDIT ANY THINGS HERE
  printf("\n");
  system ("pause");
  return(0);
}