polynomial.c

#include<stdio.h>
#include<stdlib.h>

typedef struct link {
    int coeff;
    int pow;
    struct link * next;
} poly;

/** The prototypes */
void create_poly(poly **);
void show_poly(poly *);
void add_poly(poly **, poly *, poly *);
void multiply_poly(poly **, poly *, poly *);
void write_to_txt(poly *);

int main(void) {
    poly * poly1, * poly2, * poly3,* poly4;

    printf("\n...Enter the first Polinomial...\n");
    create_poly(&poly1);
    printf("First Polinomial: ");
    show_poly(poly1);

    printf("\n...Enter the second Polinomial...\n");
    create_poly(&poly2);
    printf("Second Polinomial: ");
    show_poly(poly2);


    add_poly(&poly3, poly1, poly2);
    printf(" \n\n Resultant polynomial after addition : ");
    show_poly(poly3);


    multiply_poly(&poly4, poly1, poly2);
    printf(" \n\n Resultant polynomial after multiplication : ");
    show_poly(poly4);

    write_to_txt(poly3);
    write_to_txt(poly4);

    return 0;
}

void create_poly(poly ** node) {
    int flag; //A flag to control the menu
    int coeff, pow;
    poly * tmp_node; //To hold the temporary last address
    tmp_node = (poly *) malloc(sizeof(poly)); //create the first node
    *node = tmp_node; //Store the head address to the reference variable
    printf("{INFO}Enter the COEFFICIENT and EXPONENT in DESCENDING ORDER\n");
    do {
        printf("Enter COEFFICIENT =>");
        scanf("%d", &coeff);
        tmp_node->coeff = coeff;
        printf("Enter EXPONENT =>");
        scanf("%d", &pow);
        tmp_node->pow = pow;
        tmp_node->next = NULL;

        //Ask user for continuation
        printf("\nContinue adding more terms to the polynomial list?(Yes = 1/No = 0): ");
        scanf("%d", &flag);
        if(flag) {
            tmp_node->next = (poly *) malloc(sizeof(poly)); //Grow the list
            tmp_node = tmp_node->next;
            tmp_node->next = NULL;
        }
    } while (flag);
}


void show_poly(poly * node) {

    while(node != NULL) {
        if(node->coeff != 0){
            printf("%dx^%d", node->coeff, node->pow);
        }
        node = node->next;
        if(node != NULL)
            printf(" + ");


    }
    printf("\n");
}
void write_to_txt(poly * node) {
    FILE *f;
    f = fopen("output.txt", "a");
    while(node != NULL) {
        if(node->coeff != 0){
            fprintf(f,"%dx^%d", node->coeff, node->pow);
        }
        node = node->next;
        if(node != NULL)
            fprintf(f," + ");

    }
    fprintf(f,"\n");
    fclose(f);
}

void add_poly(poly ** result, poly * poly1, poly * poly2) {
    poly * tmp_node; //Temporary storage for the linked list
    tmp_node = (poly *) malloc(sizeof(poly));
    tmp_node->next = NULL;
    *result = tmp_node; //Copy the head address to the result linked list

    //Loop while both of the linked lists have value
    while(poly1 && poly2) {
        if (poly1->pow > poly2->pow) {
            tmp_node->pow = poly1->pow;
            tmp_node->coeff = poly1->coeff;
            poly1 = poly1->next;
        }
        else if (poly1->pow < poly2->pow) {
            tmp_node->pow = poly2->pow;
            tmp_node->coeff = poly2->coeff;
            poly2 = poly2->next;
        }
        else {
            tmp_node->pow = poly1->pow;
            tmp_node->coeff = poly1->coeff + poly2->coeff;
            poly1 = poly1->next;
            poly2 = poly2->next;
        }

        //Grow the linked list on condition
        if(poly1 && poly2) {
            tmp_node->next = (poly *) malloc(sizeof(poly));
            tmp_node = tmp_node->next;
            tmp_node->next = NULL;
        }
    }

    while(poly1 || poly2) {
        tmp_node->next = (poly *) malloc(sizeof(poly));
        tmp_node = tmp_node->next;
        tmp_node->next = NULL;

        if(poly1) {
            tmp_node->pow = poly1->pow;
            tmp_node->coeff = poly1->coeff;
            poly1 = poly1->next;
        }
        if(poly2) {
            tmp_node->pow = poly2->pow;
            tmp_node->coeff = poly2->coeff;
            poly2 = poly2->next;
        }
    }
}
void multiply_poly(poly **result, poly * poly1, poly * poly2) {
    poly * tmp_node; //Temporary storage for the linked list
    poly * temp1=poly1;
    poly * temp2=poly2;
    tmp_node = (poly *) malloc(sizeof(poly));
    tmp_node->next = NULL;
    *result = tmp_node; //Copy the head address to the result linked list

    if(!poly1 || !poly2) {
        printf("0\n");
    }else{
        while(temp1 !=NULL){

            while(temp2 !=NULL){
                tmp_node->coeff = temp1->coeff * temp2->coeff;
                tmp_node->pow = temp1->pow + temp2->pow;
                temp2 = temp2->next;
                tmp_node->next = (poly *) malloc(sizeof(poly));
                tmp_node = tmp_node->next;
                tmp_node->next = NULL;
            }
            temp1 = temp1->next;
            temp2=poly2;
        }
    }
}

Polinomial Addition and Multiplication using struct and linked list