Derive the time complexity of the carry lookahead adder.

Question

time-complexity

Comments

1 for loop required here.O(n)

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so what will be the ans to this? consider a carry look ahead adder for adding two n bit integers, built using gates of fan-in at most two. the time to perform addition using this adder is?

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sorry , it will be 1 for loop

void add()
{
int i=7,A,B,a,b,cin,num;
int n1[8],n2[8],cg[8],cp[8],sum[8];
for(i=0;i< =7;i++)
{
n1[i]=0; // Num 1
n2[i]=0; // Num 2
cg[i]=0; // Gi
cp[i]=0; // Pi
sum[i]=0; // Sum
}
A = a = get1(1);
B = b = get1(0);
i=7;
do
{
n1[i]=a%2;
a=a/2;
n2[i]=b%2;
b=b/2;
i--;
}while((a!=0)||(b!=0));
i=0;
printf("\n\t\t Binary Form",A);
printf("\n\t A = %d : ",A);
for(i=0;i< =7;i++)
printf("%d ",n1[i]);
printf("\n\t B = %d : ",B);
for(i=0;i< =7;i++)
printf("%d ",n2[i]);
cin=0;
for(i=7;i>=0;i--)
{
sum[i]=exor(cin,exor(n1[i],n2[i])); // Sum Pi (+) Bi
cg[i]=and(n1[i],n2[i]); // Gi = Ai . Bi
cp[i]=or(n1[i],n2[i]); // Pi = Ai (+) Bi
cin=or(cg[i],and(cp[i],cin)); // Cin =Gi + PiCi
}

http://cppgm.blogspot.in/2008/01/c-program-look-ahead-carry-adder.html