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Can a function return 2 values?

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Eko

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Can a function return 2 values?

Jan 21st, 2007

I have one or more functions separate from main() , that besides the return value , must also return the time it tooked to process.
How can I do that ?

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Re: Can a function return 2 values?

Jan 21st, 2007

make a parameter that is a pointer to the object you want the function to return Example:

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
int foo( size_t* time)
{
    *time = 123;
    return 1;
}
 
int main()
{
    size_t processing_time;
    int x = foo( &processing_time );
}
int foo( size_t* time)
{
    *time = 123;
    return 1;
}

int main()
{
    size_t processing_time;
    int x = foo( &processing_time );
}

If you want to profile the entire function then the function doesn't need to know anything about it.

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
int main()
{
    time_t start, end;
    start = time(0);
    foo();
    end = time(0);
  // now just subtract the two times to get processing time
 
   return 0l;
}
int main()
{
    time_t start, end;
    start = time(0);
    foo();
    end = time(0);
  // now just subtract the two times to get processing time

   return 0l;
}

Last edited by Ancient Dragon; Jan 21st, 2007 at 8:49 am.

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Eko

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Re: Can a function return 2 values?

Jan 21st, 2007

After you said , at the first method ,i came up with this:

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
#include <stdio.h>
#include <time.h>
 
 
int foo( clock_t* time)
{
    int x=0;
    while(x<1000000000)
        x++;
  *time=clock()/ (long) CLK_TCK;
    return x;
}
 
int main()
{
    clock_t processing_time;
    int x = foo( &processing_time );
    printf("%d\n x value is %d= ",processing_time,x);
 
    return 0;
}
#include <stdio.h>
#include <time.h>


int foo( clock_t* time)
{
    int x=0;
    while(x<1000000000)
        x++;
  *time=clock()/ (long) CLK_TCK;
    return x;
}

int main()
{
    clock_t processing_time;
    int x = foo( &processing_time );
    printf("%d\n x value is %d= ",processing_time,x);

    return 0;
}

I don't know if it's the greatest solution , but it works(i quess),only that isn't very accuarate .How can i make it display small time values(like 0.001 seconds)

The second method doesn't work

Last edited by Eko; Jan 21st, 2007 at 9:10 am.

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Re: Can a function return 2 values?

Jan 21st, 2007

see my second example -- you have to get the time before processing starts and again after, then subtract the two. And the time is in whole numbers. If you want fractions than divide by 100 when printing it.

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
print ("time = %f\n", (float)processing_time/100.0F);
print ("time = %f\n", (float)processing_time/100.0F);

Last edited by Ancient Dragon; Jan 21st, 2007 at 11:35 am.

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Re: Can a function return 2 values?

Jan 21st, 2007

Well for the second example , I get " error C2064: term does not evaluate to a function taking 1 arguments" at the start and end temp(0)

Last edited by Eko; Jan 21st, 2007 at 11:33 am.

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Re: Can a function return 2 values?

Jan 21st, 2007

did you include time.h? Also, if you are compiling as c++ then change variable end to something else because end is a c++ key word.

Last edited by Ancient Dragon; Jan 21st, 2007 at 11:37 am.

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Re: Can a function return 2 values?

Jan 21st, 2007

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
#include <stdio.h>
#include <time.h>
#include <dos.h>
 
int foo()
{
    int x=0;
    while(x<1000000)
        x++;
    return x;
}
 
int main()
{
    time_t start, end;
    int x,time;
    start = time(0);
    x=foo();
    end = time(0);
  // now just subtract the two times to get processing time
    time=end-start;
    printf("%d s: ",time);
 
   return 0;
}
#include <stdio.h>
#include <time.h>
#include <dos.h>

int foo()
{
    int x=0;
    while(x<1000000)
        x++;
    return x;
}

int main()
{
    time_t start, end;
    int x,time;
    start = time(0);
    x=foo();
    end = time(0);
  // now just subtract the two times to get processing time
    time=end-start;
    printf("%d s: ",time);

   return 0;
}

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Re: Can a function return 2 values?

Jan 21st, 2007

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Originally Posted by Eko

Help with Code Tags

C Syntax (Toggle Plain Text)
#include <stdio.h>
#include <time.h>
#include <dos.h>
 
int foo()
{
    int x=0;
    while(x<1000000)
        x++;
    return x;
}
 
int main()
{
    time_t start, end;
    int x,time;
    start = time(0);
    x=foo();
    end = time(0);
  // now just subtract the two times to get processing time
    time=end-start;
    printf("%d s: ",time);
 
   return 0;
}
#include <stdio.h> #include <time.h> #include <dos.h> int foo() { int x=0; while(x<1000000) x++; return x; } int main() { time_t start, end; int x,time; start = time(0); x=foo(); end = time(0); // now just subtract the two times to get processing time time=end-start; printf("%d s: ",time); return 0; }

You've named one of your variables time, and that conflicts with the time() function.