Question

My teacher asked me to create a loop that will be executed 1M times.
I tried for(long i=0;i<1000000;i++), but the program is crashing. The maximum number that the program accepts is 10.000.

Any ideas? Is this possible?

Also he asked me to create a random number >100.000. I am using rand();. Should I use a different method?

this is the code:

start_time = clock(); 
for(long i=0;i<1000000;i++){
   num1 = rand();
   num2=rand();
   gcd1(num1,num2);
}

end_time = clock();

elapsed_time = (end_time - start_time) / CLOCKS_PER_SEC;

printf( "time is %.3f seconds\n", elapsed_time );
system("pause");

This the gcd:

int gcd1(int x, int y){
    int z;
    if (x<y)
        z=x+1;
    else if (y<x)
        z=y+1;
    do{
        z=z-1;
    }
    while((x%z!=0) or (y%z!=0));
        return z;
    }
}

Answer 1

Try your loop as

for (i = 0; i < 1000000; i++) {
   do num1 = rand(); while (num1 == 0);
   do num2 = rand(); while (num2 == 0);
   gcd1(num1, num2);
}

rand() can return 0. When it does that (after more than 10000 loops), your program will set z to 0 and attempt to divide by 0.