How to clear or reset values of variables?

[geeksz]

Hi! Good day to all. I am new here. Anyway, I have been doing my homework a couple of days now and I can't seem to figure out what is wrong with my code. (I am new to C programming by the way.) We are asked to make a program that evaluates the value of a polynomial based on the user's input of N number of terms, value of x, the coefficient of each term and the constant. What bothers me is that when I did some continuous run of the program I found out that the value of the sum every after implementation of the do-while loop does not reset to 0, instead it adds up the value of the last evaluation. Any ideas how to reset it? Here is my code.

#include <stdio.h>
#include <math.h>

int terms; /*number of terms the polynomial has*/
int x; /* value of x */
int i; /* counter and exponent for evaluation using power function */
int z; /* value of each term every after iteration */
int coefficient;
int sum = 0;  /*value of the whole polynomial*/


int main(){

do{

    printf("Please enter the number of terms (Enter 0 to exit): ");
    scanf("%d", &terms);

    if (terms == 0) {

        printf("Program terminated. \n");
        system("exit");

    } else if (terms < 0){

        system ("cls");
        printf("Please enter valid number of terms! \n");
        system ("pause");

    } else {

    printf("\nPlease enter the value of x: ");
    scanf("%d", &x);
 

      for(i = terms-1; i >= 0; i--){

                if (i == 0){
                    printf("\nEnter constant: ");
                    scanf("%d", &coefficient);
                } else {
                    printf("\nEnter coefficient of x^%d: ", i);
                    scanf("%d", &coefficient);
                }
                    z = coefficient*pow (x,i);
                    sum = sum + z;

                }

            printf("The value of the polynomial is: %d \n", sum);
            system ("pause");
        }
    } while (terms!=0);
}

Thanks a lot to all those who will bother to look at my work and help me. I will mean a lot.

[claudiu]

Well think about it this way. You have a series of sequential tasks you are doing:

1) Getting the input from the user
2) Computing the polynomial
3) Printing the value you obtained
4) Back to 1)

Where in this sequence does it make sense to reset the sum to 0?

HINT: There is more than one correct answer.

[claudiu]

There is nothing complex about the question. You are doing three things in your code, getting input, computing the value of the polynomial based on the input you get and printing out that value. Where do you think you should be resetting the value of the sum?

[geeksz]

Figured it out. Thanks a lot!