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#define P 45
#define M 160
#define N 90
#include <math.h>
#include <stdlib.h>
#include <stdio.h>
struct point {
double x, y;
};
struct point vals[P];
char screen[N][M];
double function(double x)
{
return (fabs(x)+x-2);
}
int nearest(double x)
{
return ((int) (x+0.5));
}
void clear_screen()
{
int i,j;
for(i=0;i<N;i++)
for(j=0;j<M;j++)
screen[i][j]=' ';
}
void plot_screen()
{
int i,j;
for(i=N-1;i>=0;i--)
{
for(j=0;j<M;j++)
printf("%c",screen[i][j]);
printf("\n");
}
}
void calculate_values(double l, double r)
{
int i;
for(i=0;i<P;i++)
{
vals[i].x=l+i*(r-l)/(P-1);
vals[i].y=function(l+i*(r-l)/(P-1));
}
}
void horizontal(int row)
{
int j;
for(j=0;j<M;j++)
screen[row][j]='-';
}
void vertical(int col)
{
int i;
for(i=0;i<N;i++)
screen[i][col]='|';
}
void map_to_screen(double l, double r, double d, double u)
{
int i,j,i1;
double x,y;
if(l<=0&&0<=r)
horizontal(-d*(N-1)/(u-d));
if(d<=0&&0<=u)
vertical(-l*(M-1)/(r-1));
for(i1=0;i1<N;i1++)
{
x=vals[i1].x;
y=vals[i1].y;
i=((y-d)*(N-1))/(u-d);
j=((x-l)*(M-1))/(r-l);
if(nearest(i)>=0&nearest(i)<N-1&&nearest(j)>=0&&nearest(j)<M-1)
screen[i][j]='.';
}
}
int main()
{
clear_screen();
calculate_values(-5, 5.0);
map_to_screen(-5.0, 5.0, -5.0, 10.0);
plot_screen();
system("PAUSE");
return 0;
}