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2008-11-03T05:18:45Z

19 revision(s)

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'''Lab1'''

this lab is to measure" how long does it take to ececute an additon (+) operation in C?"and use data type om C(int long short float double)

Firstly I try to declare variables ,write a loop to do it , use int ,double , for loop

#include <stdio.h>
#include<time.h>
int main(void)
{
int a;
int b=0;
//try to make the number is big enough
for (a=0;a<100000;a++){
b=b+a;
}
clock();
printf("%d\n", b);
return 0;
}

But i got the wrong number , because the function clock() is in wrong way.

#include <stdio.h>
#include<time.h>
int main(void)
{
int a;
int b=0;
clock_t t0=clock();
for (a=0;a<1000000000;a++){
b=b+a;
}
printf("%ld\n", clock()-t0);
return 0;
}
I got
2422

The answer looks OK,but the test is use other main data type ,and for ""short"", is not bigger than 32767,so I do again,and make sure the number is big enough,so i use two for loop to do it.

#include <stdio.h>
#include<time.h>
int main(void)
{
int a;
int b;
int c=0;
clock_t t0=clock();
for (a=0;a<32767;a++){
for(b=0;b<32767;b++){
c=c+b-c;
}
}
printf("%ld\n", clock()-t0);
return 0;
}

and I got the answer is
3406

so later i change the data type
long 3421
short 3421
double 27375
float 7234

All the data I collected from eng Lab (windows XP), and I did it again in GCL(windows vista) I got
int 3750
long 3742
short 3774
double 6155
float 6146

And I try to did it again in FCL(iMac), I got the all the data type around
340

SE250:lab-1:shua066 - Revision history

Mark: 19 revision(s)