fizyka.c

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

void findDerivative(char **dst, char *src, int deg) {
    int a = strtol(src, &src, 10);
    if (a != 0) {
        a *= deg;
    } else if (strlen(src) > 0) {
        a = deg;
    }
    *dst = malloc(1024);
    itoa(a, *dst, 10);
    if (strlen(src) > 0) {
        strcat(*dst, "*");
        strcat(*dst, src);
    }
    strcat(*dst, "*t^");
    char *c = malloc((deg - 1) / 10 + 2);
    itoa(deg - 1, c, 10);
    strcat(*dst, c);
    dst = realloc(*dst, strlen(*dst) + 1);
}

int main(void) {
    printf("podaj wspolczynniki rownania w kolejnosci od tego przy najnizszej "
           "potedze (czyli wyrazu wolnego) oddzielone spacja (jezeli ktorys "
           "jest rowny 0 to trzeba to 0 napisac): ");
    char *buf = malloc(1024);
    if (buf == NULL) {
        printf("Memory allocation error\n");
        exit(1);
    }
    fgets(buf, 1024, stdin);
    while (*buf == ' ')
        buf++;
    char **formula;
    char *ptr = buf;
    size_t degree = 0;
    while (*ptr != '\n') {
        while (*ptr != ' ' && *ptr != '\n')
            ptr++;
        degree++;
        while (*ptr == ' ')
            ptr++;
    }
    //printf("%d\n", degree);
    formula = malloc(degree * sizeof(char *));
    degree--;
    if (formula == NULL) {
        printf("Memory allocation error\n");
        exit(1);
    }
    ptr = buf;
    char *strBegin = buf;
    size_t length, i = 0;
    while (*ptr != '\n') {
        while (*ptr != ' ' && *ptr != '\n')
            ptr++;
        length = ptr - strBegin;
        //printf("***%d***\n", length);
        formula[i] = malloc(length + 1);
        strncpy(formula[i], strBegin, length);
        formula[i][length] = '\0';
        i++;
        while (*ptr == ' ')
            ptr++;
        strBegin = ptr;
    }
    free(buf);

    char **derivative = malloc(degree * sizeof(char *));
    for (size_t i = 1; i <= degree; i++) {
        findDerivative(derivative + i - 1, formula[i], i);
    }

    printf("v(t) = ");
    for (size_t i = 0; i < degree; i++) {
        printf("%s ", derivative[i]);
        if (i != degree - 1)
            printf("+ ");
        else
            printf("\n");
    }
    return 0;
}