c program for modular division of large number | CTechnotips

C code for modular division of big numbers:

#include<stdio.h>

#include<string.h>

#define MAX 10000

int validate(char []);

int modulerDivision(char[],unsigned long);

int main(){

    char dividend[MAX];

    unsigned long int divisor,remainder;

    printf("Enter dividend: ");

    scanf("%s",dividend);

    if(validate(dividend))

         return 0;

    printf("Enter divisor: ");

    scanf("%lu",&divisor);

    remainder = modulerDivision(dividend,divisor);

    printf("Modular division: %s %% %lu  =  %lu",dividend,divisor,remainder);

    return 0;

}

int validate(char num[]){

    int i=0;

    while(num[i]){

         if(num[i] < 48 || num[i]> 57){

             printf("Invalid positive integer: %s",num);

             return 1;

         }

         i++;

    }

    return 0;

}

int modulerDivision(char dividend[],unsigned long divisor){

   

    unsigned long temp=0;

    int i=0;

    while(dividend[i]){

        

         temp = temp*10 + (dividend[i] -48);

         if(temp>=divisor){

             temp = temp % divisor;

         }

   

         i++;

    }

    return temp;

}

Sample output:

Enter dividend: 123456789

Enter divisor: 56

Modular division: 123456789 % 56 = 29