C language deleting a character in char array

Question

I'm studying C language on my own. Can someone give me a hint on problem below?

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


int main() {
    char array[100];
    char deleting;
    char * ptr;
    printf("Enter a sentence : ");
    gets(array);
    printf("Removing letter : ");
    scanf("%c",&deleting);
    ptr=array;
    while(*ptr){
        if(*ptr==deleting){
            strcpy(ptr,ptr+1);
        }
        else{
            ptr++;
        }
    }
    printf("%s",array);

    return 0;
}

// There is no r letter in dederem word why it is ?

Enter a sentence : kerem ederem severem yeperem dederem

Removing letter : e

krm drm svrm yprm ddm