Here is the revised code.
I don't guarantee it works, just compiles.

Code:
#include<iostream.h>

class Shipping
{
public:
	double rate;
	char code;
};
int main(int argc, char** argv)
{
	int x;
	char method;
	Shipping info[4];
	
	info[0].code = 'a';
	info[1].code = 't';
	info[2].code = 'r';
	info[3].code = 'h';

	info[0].rate = 14.95;
	info[1].rate = 10.25;
	info[2].rate =  8.75; 
	info[3].rate = 25.99;
	cout<<"Please enter a shipping method code: ";
	cin>>method;
	
	for(x=0; x<4; ++x)
	{
		if( method==info[x].code)
			cout<<"The rate for your shipping method is $"<<info[x].rate;
		if(x==4) // you had x = 4 that is assignment
			cout<<"You have entered an incorrect shipping method";
	}
	return 0; // indicate sucess
}