sk2 du - kalkulacka

sk2/Makefile

@@ -0,0 +1,16 @@
+CC=gcc
+CFLAGS=-Wall -lm
+
+all: calculator
+
+calculator: main.o calculator.o
+	$(CC) main.o calculator.o -o calculator $(CFLAGS)
+
+main.o: main.c calculator.h
+	$(CC) -c main.c
+
+calculator.o: calculator.c calculator.h
+	$(CC) -c calculator.c
+
+clean:
+	rm -f *.o calculator

sk2/README.md

@@ -0,0 +1,25 @@
+# Vedecká kalkulačka v jazyku C
+
+## Zadanie
+Naprogramovať vedeckú kalkulačku, ktorá vyhodnocuje matematické výrazy
+v infixnej notácii so zátvorkami a vedeckými funkciami.
+
+## Funkčnosť
+Program podporuje:
+- reálne čísla s presnosťou double
+- sčítanie (+), odčítanie (-), násobenie (*), delenie (/), zátvorky
+- sin, cos, odmocninu (sqrt), druhú mocninu (pow), log
+
+## Riešenie
+Výraz je najprv prekonvertovaný z infixnej do postfixovej notácie
+(Shunting-yard algoritmus).
+Postfixový výraz je následne vyhodnotený pomocou zásobníka.
+
+## Podmienky fungovania
+- prekladač GCC
+- knižnica math.h
+
+## Použité zdroje
+- Shunting Yard Algorithm - Edsger Dijkstra
+- Dokumentácia jazyka C
+- math.h

sk2/calculator.c

@@ -0,0 +1,122 @@
+#include "calculator.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <math.h>
+
+#define MAX 256
+#define DEG_TO_RAD(x) ((x) * M_PI / 180.0)
+
+typedef struct {
+    double data[MAX];
+    int top;
+} DoubleStack;
+
+typedef struct {
+    char data[MAX][10];
+    int top;
+} StringStack;
+
+//funckie stacku
+void push_double(DoubleStack *s, double v) { s->data[++s->top] = v; }
+double pop_double(DoubleStack *s) { return s->data[s->top--]; }
+
+void push_string(StringStack *s, const char *v) { strcpy(s->data[++s->top], v); }
+char *pop_string(StringStack *s) { return s->data[s->top--]; }
+char *peek_string(StringStack *s) { return s->data[s->top]; }
+
+//priority operatorov
+int priority(const char *op) {
+    if (!strcmp(op, "+") || !strcmp(op, "-")) return 1;
+    if (!strcmp(op, "*") || !strcmp(op, "/")) return 2;
+    if (!strcmp(op, "sin") || !strcmp(op, "cos") ||
+        !strcmp(op, "sqrt") || !strcmp(op, "log") ||
+        !strcmp(op, "pow")) return 3;
+    return 0;
+}
+
+//infix na postfix
+int infix_to_postfix(const char *infix, char postfix[][10]) {
+    StringStack ops = {.top = -1};
+    int k = 0;
+
+    for (int i = 0; infix[i]; ) {
+        if (isspace(infix[i])) { i++; continue; }
+
+        if (isdigit(infix[i]) || infix[i] == '.') {
+            char num[10];
+            int j = 0;
+            while (isdigit(infix[i]) || infix[i] == '.')
+                num[j++] = infix[i++];
+            num[j] = '\0';
+            strcpy(postfix[k++], num);
+        }
+        else if (isalpha(infix[i])) {
+            char func[10];
+            int j = 0;
+            while (isalpha(infix[i]))
+                func[j++] = infix[i++];
+            func[j] = '\0';
+            push_string(&ops, func);
+        }
+        else if (infix[i] == '(') {
+            char t[2] = "(";
+            push_string(&ops, t);
+            i++;
+        }
+        else if (infix[i] == ')') {
+            while (ops.top != -1 && strcmp(peek_string(&ops), "("))
+                strcpy(postfix[k++], pop_string(&ops));
+            pop_string(&ops);
+            i++;
+        }
+        else {
+            char op[2] = {infix[i++], '\0'};
+            while (ops.top != -1 &&
+                   priority(peek_string(&ops)) >= priority(op))
+                strcpy(postfix[k++], pop_string(&ops));
+            push_string(&ops, op);
+        }
+    }
+
+    while (ops.top != -1)
+        strcpy(postfix[k++], pop_string(&ops));
+
+    return k;
+}
+
+//vypocet postfixu
+double evaluate_postfix(char postfix[][10], int n) {
+    DoubleStack s = {.top = -1};
+
+    for (int i = 0; i < n; i++) {
+        if (isdigit(postfix[i][0]) || postfix[i][0] == '.') {
+            push_double(&s, atof(postfix[i]));
+        }
+        else {
+            double b = pop_double(&s);
+            double a = (!strcmp(postfix[i], "sin") ||
+                        !strcmp(postfix[i], "cos") ||
+                        !strcmp(postfix[i], "sqrt") ||
+                        !strcmp(postfix[i], "log")) ? 0 : pop_double(&s);
+
+            if (!strcmp(postfix[i], "+")) push_double(&s, a + b);
+            else if (!strcmp(postfix[i], "-")) push_double(&s, a - b);
+            else if (!strcmp(postfix[i], "*")) push_double(&s, a * b);
+            else if (!strcmp(postfix[i], "/")) push_double(&s, a / b);
+            else if (!strcmp(postfix[i], "sin")) push_double(&s, sin(DEG_TO_RAD(b)));
+            else if (!strcmp(postfix[i], "cos")) push_double(&s, cos(DEG_TO_RAD(b)));
+            else if (!strcmp(postfix[i], "sqrt")) push_double(&s, sqrt(b));
+            else if (!strcmp(postfix[i], "log")) push_double(&s, log10(b));
+            else if (!strcmp(postfix[i], "pow")) push_double(&s, pow(a, b));
+        }
+    }
+    return pop_double(&s);
+}
+
+double evaluate_expression(const char *expression) {
+    char postfix[MAX][10];
+    int n = infix_to_postfix(expression, postfix);
+    return evaluate_postfix(postfix, n);
+}

sk2/calculator.h

@@ -0,0 +1,6 @@
+#ifndef CALCULATOR_H
+#define CALCULATOR_H
+
+double evaluate_expression(const char *expression);
+
+#endif

sk2/main.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+#include "calculator.h"
+
+int main() {
+    char expr[256];
+
+    printf("Zadaj vyraz: ");
+    fgets(expr, sizeof(expr), stdin);
+
+    double result = evaluate_expression(expr);
+    printf("Vysledok: %.2f\n", result);
+
+    return 0;
+}