void main(){ int a,b;char op;printf("输入一个数");scanf("%d",&a);printf("\n输入运算符:");scanf("%s",&op);printf("\n输入另一个数");scanf("%d",&b);switch(op){ case '+':printf("\n =%d\n",a+b);break;case '-':printf("\n =%d\n",a-b);break;c...