rand() and syntax error
 

This is my code:



#include <iostream>
#include <cstdlib>
#include <cmath>

using namespace std;

int main(void)
{ int atHome = 0;
int stepsToTry = 5000;
double x = 0;
double y = 0;
double dx = 0;
double dy = 0;
double angle;
const double PI = 4*atan(1.0);
cout << "Will Waldo make it home?\n\n";
cout << "Input an int to start the random number generator: ";
int myStart;
cin >> myStart;
srand(myStart);
for (int i = 0; i < stepsToTry; i = i + 1)
{ rand()
do
{ double angle = 2*PI*rand()/RAND_MAX;
dx = cos(angle);
dy = sin(angle);
}while (atHome = 0);
do
{ y = y + dy;
}while (y >= -10 && y <= 10);
do
{ x = x + dx;
}while (x >= -10 && x <= 10);
if (x>=8 && x<=10)
{ if(y >= 8 && y <= 10)
{ atHome = 1;
}
}
}
if (atHome)
{ cout << "Waldo made it home after taking " << i << "steps!\n";
}
else
{ cout << "Waldo is still lost after taking" << stepsToTry << "steps\n\n";
cout << "Please play again and try to get Waldo home!\n";
}
return 0;
}

And this is my error message:

waldo.cpp: In function 'int main()':
waldo.cpp:24: synatx error before 'do':
waldo.cpp: At global scope:
waldo.cpp:41: syntax error before 'if':
waldo.cpp:46: syantax error before '<<' token:

I'm not exactly sure how to use rand() and I bet that's my problem. Could someone help please?

Your call to rand() should have a semi-colon (;) after it. That's likely the source of your syntax error. rand() returns an integer between 0 and RAND_MAX. An easy way to get a random number between 0 and some_number is to do:
If upper_limit is 50 it will return a number between 0 and 49 inclusive. The random number generator needs to be seeded if you want a different random number every time. srand() is used to do this. A common seed is the current time. You only want to call srand() once in your program, so somewhere before your first call to rand() you might do: srand(time(0));

Okay I did that and the syntax errors went away. Now I get:

waldo.cpp: In function 'int main()':
waldo.cpp:41: name lookup of 'i' changed for new ISO 'for' scoping
waldo.cpp:21: using obsolete binding at 'i'