c - Program crashes when trying to read numbers with scanf

Question

A message like this appears, when i run this code. Project.exe has stopped working

Some of my other code works, but this seems to throw me an error.

#include<stdio.h>
#include<conio.h>

void main()
{
    int n1, n2, sum;

    puts("first number");
    scanf("%d", n1);
    fflush(stdin);
    puts("second number");
    scanf("%d", n2);
    sum = n1 + n2;

    printf("%d + %d = %d", n1, n2, sum);

    getch();

}

I basically want to add two numbers.

Answer 1

scanf takes the address of the variable in which it stores the input value. You need to change your scanf calls to

scanf("%d", &n1);
scanf("%d", &n2);
//          ^ note the & operator

Also, note that it's undefined behaviour to call fflush on an input stream. So, fflush(stdin) is not correct. You need to manually read and discard extraneous input left over in the stdin stream.