CS 24 git Recitation — graphing program example

function.c

#include <math.h>

double y(double x) {
    return sin(x);
}

graph.c

#include <math.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <unistd.h>

double y(double x);

void graph(double min_x, double max_x, double min_y, double max_y) {
    struct winsize term_size;
    ioctl(STDOUT_FILENO, TIOCGWINSZ, &term_size);
    int zero_col = round(min_x / (min_x - max_x) * term_size.ws_col - 0.5),
        zero_row = round(max_y / (max_y - min_y) * term_size.ws_row - 0.5);
    int col_rows[term_size.ws_col];
    for (int col = 0; col < term_size.ws_col; col++) {
        double x = min_x + (max_x - min_x) * (col + 0.5) / term_size.ws_col;
        col_rows[col] =
            round((max_y - y(x)) / (max_y - min_y) * term_size.ws_row - 0.5);
    }
    for (int row = 0; row < term_size.ws_row; row++) {
        for (int col = 0; col < term_size.ws_col; col++) {
            putchar(
                col_rows[col] == row ? 'o' :
                row == zero_row && col == zero_col ? '+' :
                row == zero_row ? '-' :
                col == zero_col ? '|' :
                ' '
            );
        }
        putchar('\n');
    }
}

main.c

#include <stdio.h>
#include <stdlib.h>

void graph(double min_x, double max_x, double min_y, double max_y);

int main(int argc, char **argv) {
    if (argc != 5) {
        fprintf(stderr, "Usage: %s min_x max_x min_y max_y\n", argv[0]);
        return 1;
    }

    double min_x = atof(argv[1]), max_x = atof(argv[2]),
           min_y = atof(argv[3]), max_y = atof(argv[4]);
    if (!(min_x < max_x && min_y < max_y)) {
        fputs("Invalid bounds\n", stderr);
        return 1;
    }

    graph(min_x, max_x, min_y, max_y);
}

Makefile

CC = clang-with-asan
CFLAGS = -Wall -Wextra

graph: function.o graph.o main.o
	$(CC) $(CFLAGS) -lm $^ -o $@

%.o: %.c
	$(CC) $(CFLAGS) -c $^ -o $@