Difference between getch() and scanf() functions

Question

I had difficulties while executing the following code. The variable 't' take a null value after complete one execution. The problem was solved by using getch() instead of scanf(). But i don't know why it's happening. Any explainations ? This is the program which didn't work.

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
char t;
void main()
{
    while(1)
    {
        scanf("%c",&t);
        printf("\nValue of t = %c",t);
        printf("\nContinue (Y/N):");
        char a=getche();
        if(a=='n' || a=='N')
        exit(0);
   }
}

Now, this is the program which executes correctly.

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
char t;
void main()
{
    while(1)
    {
         t=getch();
         printf("\nValue of t = %c",t);
         printf("\nContinue (Y/N):");
         char a=getche();
         if(a=='n' || a=='N')
         exit(0);
    }
}

Answer 1

When you read a character,

scanf("%c",&t);

there's a newline left behind in the input stream which causes the subsequent scanf() to skip input in the loop.

Note that getch() is non-standard function. You can use getchar() instead.

Or Change it to:

scanf(" %c",&t); 

Notice the space in the format specifier which ensures all the whitespaces are skipped by scanf() before reading a character for %c.