程序代码：

#include <stdio.h>
#include <math.h>


int main( void ) 
{
    int c, r;
    int x, y;
    float xmin, ymin, xmax, ymax;    
    float x1, y1, x2, y2, x3, y3;  
    float x0, y0;
    float m1, m2, m3;


     
    printf("Enter c and r: ");
    scanf("%d %d", &r,&c);
      
    printf("Enter xmin, ymin: ");
    scanf("%f %f", &xmin, &ymin);
    
    printf("Enter xmax, ymax: ");
    scanf("%f %f", &xmax, &ymax); 
    
    printf("Enter x1, y1, x2, y2, x3, y3: ");
    scanf("%f %f %f %f %f %f", &x1, &y1, &x2, &y2, &x3, &y3);

    for(x = 0; x <= c + 1; x++) {        
        for(y = 0; y <= r + 1; y++) {
            
            x0 = ((xmax - xmin) / c) * (c - x) + xmin;
            y0 = ((ymax - ymin) / r) * (y - 1) + ymin;            
            
            m1 = ((y3 - y1) / (x3 -x1)) * (x0 - x3) + y3;
            m2 = ((y3 - y2) / (x3 -x2)) * (x0 - x2) + y2; 
            m3 = ((y1 - y2) / (x1 -x2)) * (x0 - x1) + y1;
            
            
            if(((x == 0) && (y == 0)) || ((x == c + 1) && (y == 0)) || ((x == 0) && (y == r + 1)) || ((x == c + 1) && (y == r + 1))) {
                printf("+");
            }    
            else if((x == 0) || (x == c + 1)){
                printf("-");
            }      
            
            else if((y == 0) || (y == r + 1)){
                printf("|");
            }    
  
            else if((y0 >= m1) && (y0 <= m2) && (y0 >= m3)){
                printf("*");
            }
            
            else{
                printf(" ");
            }
        }
        printf("\n");                  
    }   
    
    return 0;
}

程序代码：

#include <stdio.h>

int main( void )
{
    unsigned c=11, r=7;
    double xmin=-1, xmax=1;
    double ymin= 0, ymax=1;

    double x1=-0.40, y1=-0.1;
    double x2= 0.95, y2= 1.1;
    double x3=-1.00, y3=0.33;

    for( unsigned y=0; y<=r+1; ++y )
    {
        for( unsigned x=0; x<=c+1; ++x )
        {
            if( (x==0 || x==c+1) && (y==0 || y==r+1) )
                putchar( '+' );
            else if( x==0 || x==c+1 )
                putchar( '|' );
            else if( y==0 || y==r+1 )
                putchar( '-' );
            else
            {
                double x0 = (xmax-xmin)/(c-1) * (x-1) + xmin;
                double y0 = ymax - (ymax-ymin)/(r-1) * (y-1);

                double m12 = (y2-y1)/(x2-x1) * (x0-x1) + y1;
                double m23 = (y3-y2)/(x3-x2) * (x0-x2) + y2;
                double m31 = (y1-y3)/(x1-x3) * (x0-x3) + y3;

                if( y0>=m12 && y0<m23 && y0>m31 )
                    putchar( '*' );
                else
                    putchar( ' ' );
            }
           
        }
        putchar( '\n' );
    }

    return 0;
}