generic root means: in this we do addition of a given number until reached a single digit after addition . For example: Generic root of 784: 7 + 8 + 4 = 19 since 19 is a two digit numbers so 1 + 9 = 10.then again add 1 +0=1 So, generic root of 784 = 1

 #include<stdio.h>
    int main(){
    long int num, sum, r;
    printf("\n Enter a number:-");
    scanf("%d",&amp;num);
    while(num&gt;10){
    sum=0;
    while(num)
                   {
                         r=num%10;                           //we are taking modulus of the number
                         num=num/10;                         //now dividing number by 10
                         sum=sum+r;                              //take variable sum and store the value of r
                    }
    if(sum&gt;10)
              num=sum;
    else
    break;
    }
    printf("\n Sum of the digits in single digit is: %d",sum);
    return 0;
    }

Sample output:
Enter any number: 245
Generic root: 2