c语言问题 请问如何随机产生加减乘除任意一种运算符号呢答:include <stdlib.h>#include int main(){int a,b,i,s,num,n=0;char ch,cal[4]={'+','-','*','/'};srand(time(NULL));for(i=0;i<10;i++){a=rand()%10+1;ch=cal[rand()%4];b=rand()%10+1;printf("%d%c%d=",a,ch,b);switch(ch){case '+':s=a+b;break;ca...