131 lines
2.9 KiB
C
131 lines
2.9 KiB
C
#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#define STACK_SIZE 10
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float stack[STACK_SIZE];
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int stack_top = -1;
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bool is_number(char *string) {
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char *end;
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strtof(string, &end);
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return end != string && *end == '\n';
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}
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bool is_operation(char *string) {
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return strlen(string) == 2 && (string[0] == '+' || string[0] == '-' || string[0] == '*' || string[0] == '/');
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}
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float calculator(float n1, float n2, char operation) {
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if (operation == '+') {
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return n1 + n2;
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}
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else if (operation == '-') {
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return n1 - n2;
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}
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else if (operation == '*') {
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return n1 * n2;
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}
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else if (operation == '/') {
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if (n2 != 0) {
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return n1 / n2;
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} else {
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printf("Error: division by zero\n");
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return 0;
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}
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}
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return 0;
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}
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void push(float number) {
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if (stack_top < STACK_SIZE - 1) {
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stack[++stack_top] = number;
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} else {
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printf("Error: stack overflow\n");
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}
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}
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float pop() {
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if (stack_top >= 0) {
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return stack[stack_top--];
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} else {
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printf("Error: stack is empty\n");
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return 0;
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}
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}
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int main() {
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char arr[50];
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char *pend;
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stack_top = -1;
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bool first_output = true;
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bool operation_successful = true;
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while (fgets(arr, 50, stdin)) {
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if (arr[0] == '\n' || arr[0] == EOF) {
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break;
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}
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if (is_number(arr)) {
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float number = strtof(arr, &pend);
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push(number);
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if (!first_output) {
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printf(" ");
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}
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printf("%.2f", number);
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first_output = false;
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operation_successful = true;
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}
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else if (is_operation(arr)) {
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if (stack_top < 1) {
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if (!first_output) {
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printf(" ");
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}
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printf("no input");
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first_output = false;
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operation_successful = false;
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continue;
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}
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float n2 = pop();
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float n1 = pop();
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char operation = arr[0];
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float result = calculator(n1, n2, operation);
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push(result);
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if (!first_output) {
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printf(" ");
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}
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printf("%.2f", result);
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first_output = false;
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operation_successful = true;
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}
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else {
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if (!first_output) {
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printf(" ");
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}
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printf("no input");
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first_output = false;
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operation_successful = false;
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continue;
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}
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}
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if (operation_successful && stack_top == 0) {
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if (!first_output) {
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printf(" ");
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}
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printf("%.2f", pop());
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} else if (!operation_successful) {
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if (!first_output) {
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printf(" ");
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}
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printf("no input");
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}
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printf("\n");
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return 0;
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}
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