Problem with running and compiling c with Git Bash on Windows - c

Question

screenshot
I'm fairly new to all of this, so if it is possible could help be really dumbed down for me thank you :).
So I've had about 1 semester of coding at Uni, and we were learning C. Wanting to practice during my holiday I've done some research and opted to download Atom, installed the Gpp-compiler packages, MinGw and created a path, installed git bash etc. according to all the online instructions I could find.
However when I finally thought I was done with all the set up, a problem occured. As I was testing things out, I realised I couldn't run things properly like I was doing on the uni terminal and gedit.
Shown in my screenshot, shouldn't "hello world" be printed first after I try to run it, then I could enter a value and it should print the value or something.
However after running it would come up blank, until I enter something random and then it would print all at once.
Not sure what's happening here or what I did wrong, any guidance would be great thank you.
Edit: this only seems to be a problem, when I use scanf. Without it, everything prints out in order.
My code:
#include <stdio.h>
int main (void) {
int value;
printf("hello world\n");
scanf("%d", &value);
printf("%d", value);
return 0;
}
when I try to call, it comes out blank until I input 45, then it prints out "hello world" "45"
FNATIC P1#PC MINGW64 ~/OneDrive/Documents/CPP
$ gcc -o main main.c
FNATIC P1#PC MINGW64 ~/OneDrive/Documents/CPP
$ ./main
45
hello world
45
Another example:
#include <stdio.h>
#include <math.h>
int main(void) {
double sideA, sideB, sideC;
double s, area;
printf("Please enter 3 sides of your triangle: \n");
scanf("%lf %lf %lf", &sideA, &sideB, &sideC);
s = (sideA + sideB + sideC) / 2;
area = sqrt(s * (s - sideA) * (s - sideB) * (s - sideC));
printf("%lf\n", area);
return 0;
}
Output: nothing came out until I entered (2 3 4) and (5.31 4.2 7.77)
FNATIC P1#PC MINGW64 ~/OneDrive/Documents/CPP
$ ./heron
2 3 4
Please enter 3 sides of your triangle:
2.904738
FNATIC P1#PC MINGW64 ~/OneDrive/Documents/CPP
$ ./heron
5.31 4.2 7.77
Please enter 3 sides of your triangle:
10.542172