#include<stdio.h> int main() { double a,c; char b; scanf("%lf%c%lf",&a,&b,&c); if(b!='+'&&b!='-'&&b!='*'&&b!='/') printf("Invalid operation!"); switch(b) { case '+': printf("%.4lf+%.4lf=%.4lf",a,c,a+c); break; case '-': printf(&...
