Question

Write a function isqrt that computes the integer square root of a nonnegative inte- ger. Write a unit test that adequately exercises your function. The function prototype should be int isqrt (int n, int isr) Your function should return 0 if successful and -1 otherwise. Lack of success means that n is negative or s is a NULL pointer. In all other cases, isqrt should write the result to the location pointed by isr This is a non-trivial problem at this stage of your programming careers. Let's solve it one step at a time. First, let's more precisely define what you need to do. The integer square root of a nonnegative integer n is the largest integer s such that s2 S n. For example, the integer square root of all integers between 25 and 35 (both included) is 5, but the integer square root of 24 is 4 and the integer square root of 36 is 6. The largest integer that is not greater than is called the floor of z and is often written d. With this notation, our problem asks you to compute LVnj Our strategy is quite simple: We run through all the perfect squares 0 0 0, 1.1-1. 2 2 4, 3. 3 9, 4.4-16, 5 5 25,
I could not figure how to do it and tried times and times and still could finish under gcc. so please help in c language.thanks

Answer 1

The following C code gives you the required function along with main function but you will require only isqrt function

#include<stdio.h>
int main()
{
int n;
printf("Enter a positive number: ");
scanf("%d",&n);
int res, *ptr;
ptr = &res;
int d = isqrt(n, ptr);
if(d==-1)
printf("Error");
else
printf("Res = %d", *ptr);
return 0;
}//end of main function

int isqrt(int n, int *isr)
{
if(n<0 || isr == NULL)
return -1;
int i,res, sum = 0;

for(i=1;sum<=n; i+=2)
{
sum +=i;
res = i/2;
}
* isr = res;
return 0;
}

Output:

Enter a positive number: 34 6 42 Press any key to continue.

Enter a positive number: 36 Res-6 Process returned e (exe) execution time: 3.961 s Press any key to continue. 938

Hope it helps, do give your response.