sscanf reads what it's not supposed to - c

Question

I've recently encountered a problem with sscanf(), which I'm using to parse a polynomial.
The problem is, that this sscanf returns 1:
if (sscanf(pTemp, "%lfx\0", &tempBuf)) {
while reading the following:
4x^2\0-4x\01\t\0\0\0\0\0\0\0\0\0
but it's supposed to return 0 (obviously).
And this part of code has successfully read the right thing just before that, so I have no clue on what goes wrong.
I've tried replacing \t with such things, as * /, this didn't help. sscanf keeps recognizing 1(something) as %lfx, while supposed to return 0 and move forward.
What's the problem with it and how can I solve it except rewriting the code without using sscanf?
Here is the code itself(comments and printfs are in Russian, but they don't mean anything to the problem):
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <locale.h>
#include <math.h>
#include <ctype.h>
#include <string.h>
typedef struct polynom {
double* coeffs;
int power;
} polynom;
void main() {
setlocale(LC_ALL, "RUS");
char bufRead, flagNeg = 0, numExp = 0, xExp = 0, powExp = 0, xNotExp = 0, powAlrSet = 0, *tempReadStr, *pTemp, tempReadC = 0;
int power = 0, apprAcc = 0, cnt = 0, prolongCnt = 0;
double tempBuf = 0;
polynom* polynomIn, * polynomDer, * polynom0;
tempReadStr = calloc(52, sizeof(char));
if (!tempReadStr) {
printf("Не хватает памяти для строки ввода. Попробуйте закрыть все ненужные приложения и повторить попытку.");
return 0;
}
printf("Введите многочлен: ");
//ввод самого многочлена в строку
while (1) {
scanf("%c", &tempReadC);
if (tempReadC == '\n') {
tempReadStr[cnt++] = ' ';
break;
}
if (!isdigit(tempReadC) && (tempReadC != '+') && (tempReadC != '-') && (tempReadC != 'x') && (tempReadC != '^')) {
printf("Недопустимый символ: %c. Проверьте правильность ввода.", tempReadC);
return;
}
else {
if (cnt < 50 + prolongCnt * 50) {
if ((cnt != 0) && (tempReadC == '-')) {
tempReadStr[cnt++] = ' ';
}
if (tempReadC == '+') {
tempReadStr[cnt++] = ' ';
}
else {
tempReadStr[cnt++] = tempReadC;
}
}
else {
pTemp = realloc(tempReadStr, (52 + (++prolongCnt * 50)) * sizeof(char));
if (!pTemp) {
printf("Не хватает памяти для строки ввода. Попробуйте закрыть все ненужные приложения и повторить попытку.");
return 0;
}
tempReadStr = pTemp;
for (int j = 52 + ((prolongCnt - 1) * 50); j < 52 + (prolongCnt * 50); j++) {
tempReadStr[j] = '\0';
}
if ((cnt != 0) && (tempReadC == '-')) {
tempReadStr[cnt++] = ' ';
}
if (tempReadC == '+') {
tempReadStr[cnt++] = ' ';
}
else {
tempReadStr[cnt++] = tempReadC;
}
}
}
}
//printf("\n%s", tempReadStr);
pTemp = strtok(tempReadStr, " ");
//блок интерпретации полученной строки
while (1) {
if (!pTemp) {
break;
}
if (sscanf(pTemp, " ")) {
break;
}
/*if (sscanf(pTemp, "+")) {
}*/
if (sscanf(pTemp, "%lfx^%d", &tempBuf, &power) == 2) {
if (powAlrSet) {
if (polynomIn->power < power) {
printf("Встечена степень, большая, чем первая введённая. Введите многочлен, начиная с наибольшей степени.");
return;
}
else {
polynomIn->coeffs[power] = tempBuf;
}
}
else {
polynomIn = calloc(1, sizeof(polynom));
if (!polynomIn) {
printf("Ошибка выделения памяти.");
return;
}
polynomIn->power = power;
polynomIn->coeffs = calloc(power + 1, sizeof(double));
if (!polynomIn->coeffs) {
printf("Ошибка выделения памяти.");
return;
}
powAlrSet = 1;
polynomIn->coeffs[power] = tempBuf;
}
pTemp = strtok(NULL, " ");
continue;
}
if (sscanf(pTemp, "x^%d", &power)) {
if (powAlrSet) {
if (polynomIn->power < power) {
printf("Встечена степень, большая, чем первая введённая. Введите многочлен, начиная с наибольшей степени.");
return;
}
else {
polynomIn->coeffs[power] = 1;
}
}
else {
polynomIn = calloc(1, sizeof(polynom));
if (!polynomIn) {
printf("Ошибка выделения памяти.");
return;
}
polynomIn->power = power;
polynomIn->coeffs = calloc(power + 1, sizeof(double));
if (!polynomIn->coeffs) {
printf("Ошибка выделения памяти.");
return;
}
powAlrSet = 1;
polynomIn->coeffs[power] = 1;
}
pTemp = strtok(NULL, " ");
continue;
}
if (sscanf(pTemp, "-x^%d", &power)) {
if (powAlrSet) {
if (polynomIn->power < power) {
printf("Встечена степень, большая, чем первая введённая. Введите многочлен, начиная с наибольшей степени.");
return;
}
else {
polynomIn->coeffs[power] = -1;
}
}
else {
polynomIn = calloc(1, sizeof(polynom));
if (!polynomIn) {
printf("Ошибка выделения памяти.");
return;
}
polynomIn->power = power;
polynomIn->coeffs = calloc(power + 1, sizeof(double));
if (!polynomIn->coeffs) {
printf("Ошибка выделения памяти.");
return;
}
powAlrSet = 1;
polynomIn->coeffs[power] = -1;
}
pTemp = strtok(NULL, " ");
continue;
}
if (sscanf(pTemp, "%lfx", &tempBuf)) {
if (powAlrSet) {
polynomIn->coeffs[1] = tempBuf;
}
else {
polynomIn = calloc(1, sizeof(polynom));
if (!polynomIn) {
printf("Ошибка выделения памяти.");
return;
}
polynomIn->power = 1;
polynomIn->coeffs = calloc(2, sizeof(double));
if (!polynomIn->coeffs) {
printf("Ошибка выделения памяти.");
return;
}
powAlrSet = 1;
polynomIn->coeffs[1] = tempBuf;
}
pTemp = strtok(NULL, " ");
continue;
}
if (sscanf(pTemp, "x")) {
if (powAlrSet) {
polynomIn->coeffs[1] = 1;
}
else {
polynomIn = calloc(1, sizeof(polynom));
if (!polynomIn) {
printf("Ошибка выделения памяти.");
return;
}
polynomIn->power = 1;
polynomIn->coeffs = calloc(2, sizeof(double));
if (!polynomIn->coeffs) {
printf("Ошибка выделения памяти.");
return;
}
powAlrSet = 1;
polynomIn->coeffs[1] = 1;
}
pTemp = strtok(NULL, " ");
continue;
}
if (sscanf(pTemp, "-x")) {
if (powAlrSet) {
polynomIn->coeffs[1] = -1;
}
else {
polynomIn = calloc(1, sizeof(polynom));
if (!polynomIn) {
printf("Ошибка выделения памяти.");
return;
}
polynomIn->power = 1;
polynomIn->coeffs = calloc(2, sizeof(double));
if (!polynomIn->coeffs) {
printf("Ошибка выделения памяти.");
return;
}
powAlrSet = 1;
polynomIn->coeffs[1] = -1;
}
pTemp = strtok(NULL, " ");
continue;
}
if (sscanf(pTemp, "%lf", &tempBuf)) {
if (!powAlrSet) {
printf("Ввод многочлена принято начинать со старшей степени.");
return;
}
else {
polynomIn->coeffs[0] = tempBuf;
}
}
}
printf("Вы ввели многочлен:\n");
for (int i = power; i >= 0; i--) {
if (polynomIn->coeffs[i]) { // != 0
if ((polynomIn->coeffs[i] > 0) && (i != power))
printf("+");
if (i) { // != 0
if (polynomIn->coeffs[i] != 1) {
if (polynomIn->coeffs[i] != -1) {
if (i != 1) {
printf("%.0lfx^%d", polynomIn->coeffs[i], i);
}
else printf("%.0lfx", polynomIn->coeffs[i]);
}
else if (i != 1) {
printf("-x^%d", i);
}
else printf("-x");
}
else if (i != 1) {
printf("x^%d", i);
}
else printf("x");
}
else {
if (polynomIn->coeffs[i]) {
printf("%.0lf", polynomIn->coeffs[i]);
}
}
}
}
}
It should give you the polynomial you enter. I tried with 4x^2-4x+1, and it gave me 4x^2+x.

Answer 1

Well, I don't know, what's the reason with sscanf(), because it tends to ignore even what goes before the first formatted input, so I've just replaced all my "-", "x", "^", with %c scanning chars to variables, which values I've checked right after that. And that worked.