Errors in a sqrt function program in c++

Question

**Essentially I was given pseudo code:

"x = 1

repeat 10 times: x = (x + n / x) / 2

return x"

And the pseudo code for the int main function (int main function to print out my n values in the cout) at the end, in order to create a sqrt function program. I get the following errors on linux2 compiler:

: In function ‘double my_sqrt_1(double)’:

:9:1: error: expected primary-expression before ‘return’

:9:1: error: expected ‘;’ before ‘return’

: In function ‘int main()’: : 15:13: error: expected unqualified-id before ‘-’ token

:~> expected primary-expression before ‘return’

Help is much appreciated!

#include <iostream> 
#include <math.h> 
using namespace std; 

double my_sqrt_1(double n) 
{ 
for (int x= 1; x<10; ++x) 
cout<< x << '\t' << x=(x+n/x)/2 << 
return x; 
} 

int main() 
{ 
int n= 3.141459; 
int k= -100,-10,-1,0,1,10,and 100; 
for(auto k : { -100,-10,-1,0,1,10,100}){ 
n=3.14159 * pow (10.0,k); 
cout << "print n,sqrt(n),and my_sqrt_1(n)" ; 
return 0; 
} 
}

You seem to be trying to use cout to do everything. What do you expect cout << "print n,sqrt(n),and my_sqrt_1(n)" to do? — user2357112 supports Monica

Matt Lacey Matt Lacey · Accepted Answer · 2013-09-17T00:05:51

You missed a semicolon at the end of the cout line:

double my_sqrt_1(double n) 
{ 
  for (int x= 1; x<10; ++x) 
    cout<< x << '\t' << x=(x+n/x)/2;
  return x; 
}

The clue is in the error:

:9:1: error: expected ‘;’ before ‘return’

Finding the source of compiler errors can be tricky for those new to C/C++, if you miss a semi-colon the line reported will often differ from the one containing the actual error. As in this case where the return line became part of the same statement as the line above.

Also here:

int k= -100,-10,-1,0,1,10,and 100;

That is not how you define an array, you should read up on the basics of those since you're new to the game, which is evident here:

cout << "print n,sqrt(n),and my_sqrt_1(n)" ;

Where you're not calling any functions but instead outputting a static string of text. You need to make the function calls and variable outputs outside of the literal string:

cout << "print " << n << "," << sqrt(n) << ", and" << my_sqrt_1(n);

Errors in a sqrt function program in c++

1 Answers