}while (‘y’== ch || ‘Y’== ch); 各位大佬，这个程序为什么会报错？

Question

一元二次方程# include <stdio.h># include <math.h> int main(void){  double a, b, c; double delta; double x1, x2; char ch; do{ printf("请输入一元二次方程的三个系数：\n"); printf("a ="); scanf("%lf", &a); printf("b ="); scanf("%lf", &b); printf("c ="); scanf("%lf", &c);  delta = b*b - 4*a*c; if(delta > 0) { x1 = (-b + sqrt(delta)) / (2*a); x2 = (-b - sqrt(delta)) / (2*a); printf("有两个解，x1 = %lf, x2 = %lf\n", x1, x2); } else if (0 == delta) {     x1 = x2 = (-b) / (2*a); printf("有唯一解， x1 = x2 = %lf\n", x1, x2); } else { printf("无实数解！\n");  } printf("继续请输入(y/n);"):    scanf(" %c", &ch);                                     }while (‘y’== ch  || ‘Y’== ch); return 0;}