Move change each element in a string and a coditional if arr[i-1]=='n'.... do : problem take a string move every character in the alphabet 13 times forward for example hello would be **uryyb**, but the trick here is that if there is a vowel in the element before then its 14 spaces so it would be **urzyb**, I got the 14 space but then nothing else happens to the other letters so I keep getting **hezlo**, but if remove the // and use this line of code 

    message[i] = message[i] + key;`

then it doesn't do the 14 and only does 13 time can someone explain what I'm doing wrong and how to fix it

    #include<stdio.h>
    
    int main()
    {
    char message[100], ch;
    int i, key;
    
    printf("Enter a message to encrypt: ");
    gets(message);
    printf("Enter key: ");
    scanf("%d", &key);
    
    for(i = 0; message[i] != '\0'; ++i){
    
    
    if(message[i] >= 'a' && message[i-1] <= 'z'){
        if(message[i-1] == 'e'){
            message[i]=message[i] + 14;
        }
        
        
    //message[i] = message[i] + key;
    
    if(message[i] > 'z'){
    message[i] = message[i] - 'z' + 'a'-1 ;
    }
    
    message[i] = message[i];
    }
    }
    
    printf("Encrypted message: %s", message);
    
    return 0;
    } 



Output is **hezlo** 
should be **urzyb**
