C code missing getchar() command in while loop first time round - c

Question

I am writing a menu system in C, the code works correctly but for some reason the first first time the while loop is entered for the menu it skips the getchar() command and runs through the while loop again, but the second time round it works?
Any ideas as to why it does this?
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "structs.h"
int main(void)
{
FILE *fp = NULL;
char fileName[25], line[200], userInput = ' ';
int len;
while (fp == NULL)
{
printf("Enter The File To Load In: \n");
scanf("%s", fileName); // Ask User For File Name
fp = fopen(fileName, "r"); // Open File To Read
if (fp == NULL)
{
perror("Error While Loading File\n");
}
}
while (userInput != 'g')
{
printf(" |User System|\n");
printf("A) Save Current Data To A File\n");
printf("B) Enter Details\n");
printf("C) View Details\n");
printf("D) Amend Details\n");
printf("E) Search by Award Title\n");
printf("F) Search by Surname\n");
printf("G) Shut Down\n");
userInput = getchar();
if (userInput == 'c')
{
fgets(line, 200, fp);
len = strlen(line);
printf("%s", line);
userInput = getchar();
}
}
}

Answer 1

After 'scanf' use
getchar();
to consume extra newline. As 'scanf' can not discard newline, first iteration of 'getchar();' take the newline.
So you shold place getchar() after scanf as to consume extra newline('\n')
scanf("%s", fileName);
getchar();
It's better to use 'fgets' instead of scanf as file name may have space.
You can use 'fgets()' as
fgets(fileName, sizeof(fileName), stdin);
fileName[strlen(fileName)-1] = 0; //Replace newline with '\0' character