125 lines
2.4 KiB
C
125 lines
2.4 KiB
C
#include<stdio.h>
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#include<assert.h>
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#include<string.h>
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#include<stdlib.h>
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#define STACK_SIZE 10
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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 push_stack(struct stack* mystack, float value)
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{
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assert(mystack->size<STACK_SIZE);
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mystack->values[mystack->size]=value;
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mystack->size+=1;
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}
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int switch_operators(const char input[])
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{
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switch (input[0])
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{
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case '+':
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return 0;
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break;
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case '-':
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return 0;
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break;
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case '*':
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return 0;
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break;
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case '/':
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return -1;
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break;
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default:
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return 1;
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break;
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}
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}
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float pop_stack(struct stack* mystack,const char input[])
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{
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assert(mystack->size>1);
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float val1=mystack->values[mystack->size-2];
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float val2=mystack->values[mystack->size-1];
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switch (input[0])
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{
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case '+':
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mystack->size-=2;
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return val1+val2;
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break;
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case '-':
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mystack->size-=2;
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return val1-val2;
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break;
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case '*':
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mystack->size-=2;
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return val1*val2;
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break;
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case '/':
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mystack->size-=2;
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return val1/val2;
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break;
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default:
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break;
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}
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}
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void print_stack(struct stack* mystack)
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{
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for(int i=0;i<mystack->size;i++)
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{
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printf("%.2f",mystack->values[i]);
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if (i<mystack->size-1)
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{
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printf(" ");
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}
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}
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printf(" \n");
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}
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int main()
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{
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struct stack mystack;
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memset(&mystack,0,sizeof(struct stack));
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char input[1000];
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while (fgets(input,sizeof(input),stdin)!=NULL)
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{
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if(input[0]==10 || input[0]==13)
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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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if((input[0]>=0 && input[0]<=47) || (input[0]>=58 && input[0]<=127))
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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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int flag=switch_operators(input);
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input[strcspn(input,"\n")]=0;
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if (flag==0 || flag==-1)
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{
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if(flag==-1 && mystack.values[mystack.size-1]==0)
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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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float op_num=pop_stack(&mystack,input);
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push_stack(&mystack,op_num);
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}
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else
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{
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char* ptr;
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float num=strtof(input,&ptr);
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push_stack(&mystack,num);
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}
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print_stack(&mystack);
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}
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return 0;
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}
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