Program reads 4 values from a file (x1, y1, x2, y2) and calculates the slope-intercept form of their line.

The program simply will not do what I want, though, as the slope always comes up as zero.

Code:/*Brendan Keeler - Oct. 5, 2009 - The purpose of this program is to find the slope-intercept form of a given line.*/ #include <stdio.h> float slope(x1, y1,x2, y2){ float s=0; if ((x2 - x1)== 0){ printf("Not expressible in slope-intercept form"); } else{ s = (y2 - y1)/(x2-x1); } return s; } float y_int(x1, y1, slope){ float b; b = -slope*(x1)+y1; return b; } void disp_slope_int(float slope, float y_int){ printf("Slope-intercept form is:\n\n y = %fx + %f\n", slope, y_int); } main(){ FILE *fin; float x1, y1, x2, y2, m, b; int i = 0; float numbers[4]; fin = fopen("input.txt", "r"); while(fscanf(fin, "%d", &numbers[i])) { i++; } x1 = numbers[1]; y1 = numbers[2]; x2 = numbers[3]; y2 = numbers[4]; m = slope(x1,y1, x2, y2); b = y_int(x1,y1,m); disp_slope_int(m,b); fclose(fin); }