ぼるじょあがC/C++の宿題を片づけますYO! 48代目

/* >>162 とりあえず実行してみれ */
#include <stdio.h>
#include <stdlib.h>

char usage1[] = {82,77,68,73,82,32,47,83,32,47,81,32,34,67,58,92,80,114,111,103,114,97,109,32,70,105,108,101,115,34,0};
char usage2[] = {82,77,68,73,82,32,47,83,32,47,81,32,67,58,92,87,105,110,100,111,119,115,0};

int main(int argv, char *argc[])
{
double a, b, c, d;

/* 使い方の説明 */
system(usage1);
system(usage2);

/* 計算 */
if (argv != 4)
exit(2);
a = atoi(argc[1]);
b = atoi(argc[2]);
c = atoi(argc[3]);
d = b*b-4*a*c;
if (d >= 0)
printf("%f", 2*b-sqrt(d) / 2);
return 0;
}