130 lines
2.5 KiB
C
130 lines
2.5 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <ctype.h>
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#include <assert.h>
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#define STACK_SIZE 50
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struct stack
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{
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float values[STACK_SIZE];
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int size;
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};
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void add(struct stack* stack, float num)
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{
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assert(stack->size < STACK_SIZE);
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stack->values[stack->size] = num;
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stack->size++;
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}
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float getnpop(struct stack* stack)
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{
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assert(stack->size > 0);
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float value = stack->values[stack->size-1];
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stack->size -= 1;
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return value;
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}
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int calculate(struct stack* stack, char operator)
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{
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if(stack->size < 2)
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{
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return 2;
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}
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float num1 = getnpop(stack);
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float num2 = getnpop(stack);
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float res = 0;
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switch(operator)
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{
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case '+':
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res = num1+num2;
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break;
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case '-':
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res = num2-num1;
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break;
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case '*':
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res = num1*num2;
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break;
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case '/':
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if(num1 == 0)
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{
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//res = 1;
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return 1;
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}
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res = num2/num1;
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break;
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}
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add(stack, res);
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return 0;
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}
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int check_op(char symb)
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{
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if(symb == '+' || symb == '-' || symb == '*' || symb == '/')
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{
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return 1;
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}
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return 0;
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}
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int main(int argc, char const *argv[])
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{
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char buf[50];
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struct stack calc_stack;
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float num = 0;
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int s = 0;
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memset(buf, 0, 50);
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memset(&calc_stack,0,sizeof(struct stack));
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while (fgets(buf, 50, stdin) != NULL)
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{
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if(buf[0] == '\n')
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{
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break;
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}
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if(buf[0] == '.')
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{
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printf("bad input\n");
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return 0;
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}
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for (int i = 0; i < strcspn(buf, "\n"); i++)
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{
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if(isalpha(buf[i]) != 0)
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{
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printf("bad input\n");
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return 0;
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}
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}
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buf[strcspn(buf, "\n")] = '\0';
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if(!check_op(buf[0]))
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{
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num = atof(buf);
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add(&calc_stack, num);
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}
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else
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{
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if(calculate(&calc_stack, buf[0]) == 1)
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{
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printf("division by zero\n");
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return 0;
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}
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else if(calculate(&calc_stack, buf[0]) == 2)
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{
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printf("not enough operands\n");
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return 0;
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}
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}
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for (int i = 0; i < calc_stack.size; i++)
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{
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printf("%.2f ", calc_stack.values[i]);
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}
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printf("\n");
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}
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printf("no input\n");
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return 0;
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}
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