117 lines
2.6 KiB
C
117 lines
2.6 KiB
C
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#define MAX 50
|
|
char infix_q[MAX];
|
|
int compare(char stack_o , char infix_o);
|
|
void infix_to_postfix();
|
|
|
|
|
|
|
|
int get_priority(char c){
|
|
if(c=='+' || c=='-'){
|
|
return 1;
|
|
}else if(c=='*' || c=='/'){
|
|
return 2;
|
|
}else if(c=='^'){
|
|
return 3;
|
|
}else{
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
int main(){
|
|
int i=0;
|
|
for(i=0;i<MAX;i++){
|
|
infix_q[i]='\0';
|
|
}
|
|
printf("\t--------------------------------------------\n");
|
|
printf("\t中序運算式轉換成後序運算式\n");
|
|
printf("\t可以使用的運算子包括:^,*,+,-,/,(,) 等\n");
|
|
printf("\t--------------------------------------------\n");
|
|
printf("\t請輸入中序運算式\n");
|
|
infix_to_postfix();
|
|
printf("\n");
|
|
return 0;
|
|
}
|
|
|
|
|
|
int compare(char stack_o,char infix_o){
|
|
// char infix_priority[9]={'#',')','+','-','*','/','^',' ','('};
|
|
// char stack_priority[8]={'#',')','+','-','*','/','^',' '};
|
|
int index_s = 0 ,index_i = 0;
|
|
while(stack_priority[index_s]!=stack_o){
|
|
index_s++;
|
|
}
|
|
while(infix_priority[index_i]!=infix_o){
|
|
index_i++;
|
|
}
|
|
return index_s/2 >= index_i/2 ? 1 : 0;
|
|
}
|
|
|
|
|
|
void infix_to_postfix() {
|
|
int rear = 0, top = 0, flag = 0, i = 0;
|
|
char stack_t[MAX];
|
|
int tag = 1;
|
|
for(i = 0; i < MAX; i++) {
|
|
stack_t[i] = '\0';
|
|
}
|
|
|
|
|
|
fgets(infix_q, MAX, stdin);
|
|
infix_q[strcspn(infix_q, "\n")] = 0;
|
|
|
|
i = 0;
|
|
while(infix_q[i] != '\0') {
|
|
i++;
|
|
rear++;
|
|
}
|
|
infix_q[rear] = '#';
|
|
printf("\t後序表示法：");
|
|
stack_t[top] = '#';
|
|
|
|
for(flag = 0; flag <= rear; flag++) {
|
|
tag = 1;
|
|
switch(infix_q[flag]) {
|
|
case ')':
|
|
while(stack_t[top] != '(') {
|
|
printf("%c", stack_t[top--]);
|
|
}
|
|
top--;
|
|
break;
|
|
case '#':
|
|
while(stack_t[top] != '#') {
|
|
printf("%c", stack_t[top--]);
|
|
}
|
|
break;
|
|
case '(':
|
|
case '*':
|
|
case '/':
|
|
case '^':
|
|
while(compare(stack_t[top], infix_q[flag]) == 1) {
|
|
printf("%c", stack_t[top--]);
|
|
}
|
|
stack_t[++top] = infix_q[flag];
|
|
break;
|
|
case '+':
|
|
case '-':
|
|
if(tag==1){
|
|
while(compare(stack_t[top], infix_q[flag]) == 1) {
|
|
printf("%c", stack_t[top--]);
|
|
}
|
|
stack_t[++top] = infix_q[flag];
|
|
break;
|
|
}else if(tag==2){
|
|
|
|
}
|
|
|
|
|
|
default:
|
|
if(infix_q[flag] != ' ') { // 忽略空格
|
|
printf("%c", infix_q[flag]);
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
}
|