#include #include #include static void usage(char *s); int main(int argc, char *argv[]) { if (argc != 4) usage(argv[0]); else { double a = atof(argv[1]); double b = atof(argv[2]); double c = atof(argv[3]); double delta = b*b - 4*a*c; if (delta < 0) printf("Pas de racine réelle\n"); else if (delta == 0) printf("Une racine double : %g\n", -b/(2*a)); else { double racine_de_delta = sqrt(delta); printf("Deux racines : %g et %g\n", (-b - racine_de_delta)/(2*a), (-b + racine_de_delta)/(2*a)); } } return EXIT_SUCCESS; } static void usage(char *s) { fprintf(stderr, "Usage: %s «a» «b» «c»\n", s); exit(EXIT_FAILURE); }