setlinestyle(j,0,3)

#include < graphics.h > 
#include < stdio.h > 
int main() {
    int i,
    j;
    int graphdriver = DETECT;
    int graphmode;
    initgraph( & graphdriver, &graphmode, "");
    cleardevice();
    for (i = 0; i < 4; i++) {
        setlinestyle(i, 0, 1);
        line(0, (i + 1) * 10, getmaxx(), (i + 1) * 10);
    }
    for (j = 0; j < 4; j++) {
        setlinestyle(j, 0, 3);
        line(0, 50 + (j + 1) * 10, getmaxx(), 50 + (j + 1) * 10);
    }
    getch();
    closegraph();
    return (0);
}