contoh program merging C++

#include
#include
#include

int main()
{
typedef struct {int nilai;
}Rekarray;

FILE *arrayA, *arrayB, *arrayC;
Rekarray rekA,rekB,rekC;

arrayA=fopen("arrayA.txt","rt");
fread(&rekA,sizeof(rekA),1,arrayA);
arrayB=fopen("arrayB.txt","rt");
fread(&rekB,sizeof(rekB),1,arrayB);
arrayC=fopen("array gabung.txt","wt");


while(!feof(arrayA) && feof(arrayB))
{
if(rekA.nilai <= rekB.nilai)
{
fwrite(&rekA,sizeof(rekA),1,arrayC);
fread(&rekA,sizeof(rekA),1,arrayA);
}
else
{
fwrite(&rekB,sizeof(rekB),1,arrayC);
fread(&rekB,sizeof(rekB),1,arrayB);
}
}

while (!feof(arrayA))
{
fwrite(&rekA,sizeof(rekA),1,arrayC);
fread(&rekA,sizeof(rekA),1,arrayA);
}

while (!feof(arrayB))
{
fwrite(&rekB,sizeof(rekB),1,arrayC);
fread(&rekB,sizeof(rekB),1,arrayB);
}

fcloseall();
system("pause");
return 0;
}