Hi all I have written the following code in C language to 'Find the sum of all the multiples of 3 or 5 below 1000' it works fine for i<10 and i<100 and also gives the right answer but for condition i<1000 the answer is in -ve something like -28345. I am trying to understand waht is wrong and how to correct it. (I have a clue of what is wrong :-) but want to hear from the experts here)

Code://Find the sum of all the multiples of 3 or 5 below 1000. #include<stdio.h> #include<conio.h> void main () { int a,b,i,iSum=0; for (i=1;i<1000;i++) { a = i%3; b = i%5; if(a==0||b==0) { iSum = iSum+i; } } printf("\nThe sum of all the multiples of 3 or 5 below 1000: %d\n", iSum); getch(); clrscr(); }