你好，scanf中的变量前面需要加&#include#includeint main(){double x1,y1,x2,y2,a;scanf("%lf %lf %lf %lf",&x1,&y1,&x2,&y2);a=sqrt(pow(x1-x2,2)+pow(y1-y2,2));printf("%.2f",a);return 0;}
