## INDEX

### C program to find power of a large number

C code for power of very big numbers:

How to get power of two very large numbers larger or beyond than long int in c programming language:

#include<stdio.h>
#include<string.h>
#define MAX 10000

char * multiply(char [],char[]);
int main(){
char a[MAX];
char *c;
int i,n;
printf("Enter the base number: ");
scanf("%s",a);
printf("Enter the power: ");
scanf("%d",&n);

printf("Power of the %s^%d: ",a,n);

c = multiply(a,"1");
for(i=0;i<n-1;i++)
c = multiply(a,c);

while(*c)
if(*c =='0')
c++;
else
break;

printf("%s",c);
return 0;
}

char * multiply(char num1[],char num2[]){
static char mul[MAX];
char a[MAX];
char b[MAX];
char c[MAX];
char temp[MAX];
int la,lb;
int i=0,j,k=0,x=0,y;
long int r=0;
long sum = 0;

while(num1[i]){
a[i] = num1[i];
i++;
}
a[i]= '\0';

i=0;
while(num2[i]){
b[i] = num2[i];
i++;
}
b[i]= '\0';

la=strlen(a)-1;
lb=strlen(b)-1;

for(i=0;i<=la;i++){
a[i] = a[i] - 48;
}

for(i=0;i<=lb;i++){
b[i] = b[i] - 48;
}

for(i=lb;i>=0;i--){
r=0;
for(j=la;j>=0;j--){
temp[k++] = (b[i]*a[j] + r)%10;
r = (b[i]*a[j]+r)/10;
}
temp[k++] = r;
x++;
for(y = 0;y<x;y++){
temp[k++] = 0;
}
}

k=0;
r=0;
for(i=0;i<la+lb+2;i++){
sum =0;
y=0;
for(j=1;j<=lb+1;j++){
if(i <= la+j){
sum = sum + temp[y+i];
}
y += j + la + 1;
}
c[k++] = (sum+r) %10;
r = (sum+r)/10;
}
c[k] = r;
j=0;
for(i=k-1;i>=0;i--){
mul[j++]=c[i] + 48;
}
mul[j]='\0';
return mul;
}

Sample output:

Enter the base number: 5
Enter the power: 100
Power of the 5^100: 78886090522101180541172856528278622
96732064351090230047702789306640625

Algorithm to find the power of large numbers:

Use array to store big numbers.

#### 1 comment:

Anonymous said...

thanx for ur post...i really happy...bcoz i m qualified in my test for this....