CODEWITHSUNDEEP
ccompiler-errorsnested-loops
Alex
Alex

Reputation: 73

C language cygwin compiler, not sure why this is happening

My job is to prove fermats theory incorrect using c. so what i did was have nested loops, its pretty easy to read.

here is the code:

#include <stdio.h>
#include <math.h>

quadtest(unsigned long long int a, unsigned long long int b, unsigned long long int c, unsigned        int n)
{
if ((pow(a,n)+pow(b,n))==pow(c,n))
    return 1;
else
    return 0;

}    

main()
{
unsigned long long int a;
unsigned long long int b;
unsigned long long int c;
unsigned int n;

//a=1;  b=1;    c=1;    n=1;
for(n=2; n<100; n++)
{
printf("\nn=%d",n);
    for(c=1; c<500; c++)
    {
        printf("\ntrying now c=%d and n=%d",c,n);       
        for(b=1; b<500; b++)
        {
            if (quadtest(a,b,c,n)) break;
            //printf("\nb=%d, n=%d",b,n);

        }
        for(a=1; a<500; a++)
        {
            if (quadtest(a,b,c,n)) break;
            //printf("\na=%d, n=%d",a,n);   
        }
    }
    printf("\nthe right values to prove fermats theory wrong are n=%d,c=%d,b=%d,a=%d",n,c,b,a);
}       





}

after being compiled, im getting "trying c=random number, n=0. n always equals 0 for some reason even though its never supposed to be 0.

im also getting something like "the right values to prove fermats theory wrong are n=99,c=500,b=0,a=500"

which once again, neither a, b, c, or n are supposed to be 0. not sure what the problem is

Upvotes: 0

Views: 101

Answers (1)

teppic
teppic

Reputation: 8195

There are two clear problems with your code:

You define several variables, and each is initialised except for a. You call a function using a uninitialised. This is undefined behaviour and could explain your problem.

Secondly, you are using the incorrect specifier in printf. %d is used for int; %llu is for unsigned long long. Using the wrong specifier can lead to incorrect values being output.

Upvotes: 1

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