How do I graph data in c++?

I am trying to make a graph using graphics.h in c++. I was following a tutorial on youtube. It seems that either due to the age of the video (perhaps the syntax has changed slightly?) or a problem on my end; I cannot even get a separate window for my graph to open. I am in completely uncharted waters for me as the limit of my coding knowledge is what you would expect to learn from a first-semester coding class. I am using DEV C++ and am compiling using "TDM-GCC 4.9.2 32-bit Release" (because the 64 bit release gives me an error in "Makefile.win" that scares me) and my program exits with a return value of 3221225477. What am i doing wrong?

#include"graphics.h"
#include<math.h>
#include<conio.h>
#include<iostream>
using namespace std;

int main() {
    
    initwindow(800,600);
    int x,y;
    line(0,300,getmaxx(),300);
    line(400,0,400,getmaxy());
    float pi=3.14159;
    
    for(int i=-360;i<=360;i++){
        
        x=(int)400+i;
        y=(int)300-sin(i*pi/100)*25;
        putpixel(x,y,WHITE);
    
    }
    
    getch();
    closegraph();
    
    return 0;
}