c語言用棧實現帶括號的簡單計算器

寫的簡單，棧部分實現比較粗略，可能有沒考慮到的地方

目錄

整體步驟分為三步：
1.棧的簡單實現
2.中綴轉換為字尾
3.字尾運算

1.棧的簡單實現

typedef struct stack{
    int value;
    char is_op;//這裡新增一個操作符判定主要是有操作符ascii可能與輸入資料重合
    stack_t* next;
}STA;
stack_t *stack_init(){
    stack_t *p = NULL;
    return p;
}
void print_stack(stack_t *stack
 
){
    if(NULL == stack ){
       // printf("stack is null! error.\n");
        printf("\n\n");
        return;
    }
    if(stack->is_op == 1){
        printf("%c ",stack->value);
    }else{
        printf("%d ",stack->value);
    }
    print_stack(stack->next);
}
void stack_push(int value, stack_t **stack
 
,char is_op){
    stack_t *p = NULL;
    p = (stack_t *)malloc(sizeof(stack_t) * 1);
    memset(p,0,sizeof(stack_t));
    p->value = value;
    p->is_op = is_op;
    p->next = *stack;
    *stack = p;
}
int stack_pop(stack_t **stack){
    if(stack == NULL){
        printf("stack is empty!\n");
        return
 
 0;
    }
    stack_t *p = *stack;
    int value;
    value = (*stack)->value;
    *stack = p->next;
    free(p);
    p=NULL;
    return value;
}
int stack_top(stack_t *stack){
    return stack->value;
}

2.中綴轉換為字尾

static char op_c[op_row][op_col]={
    {'+','-'},
    {'*','/','%'},
    {'^'},
    {'(',')'}
};
int is_operator(char ch){
    for(int i = 0;i<op_row;i++){
        for(int j = 0;j<op_col;j++){
            if(ch == op_c[i][j]){
                //printf("%c is op\n",ch);
                return true;
            }
        }
    }
  //  printf("%c is not op\n",ch);
    return false;
}
int is_pri(char cur,char befor){
    int cur_row = 0;
    int befor_row = 0;
    for(int i = 0;i<op_row;i++){
        for(int j = 0;j<op_col;j++){
            if(cur == op_c[i][j]){
                cur_row = i;
            }
            if(befor == op_c[i][j]){
                befor_row = i;
            }
        }
    }
    return cur_row-befor_row;
}
void suffix(stack_t *input,stack_t **output1){
    stack_t *stack_op = stack_init();
    stack_t *output = stack_init();
   // print_stack(input);
    while((input != NULL) && ('=' != (input->value))){
       // printf("%d %d\n",input->value,input->is_op);
        if(1 == input->is_op){
            while(stack_op != NULL){
                if((is_pri(input->value,stack_top(stack_op)) <= 0 || ')' == input->value)&& '(' != stack_op->value){
                    stack_push(stack_pop(&stack_op),&output,1);
                }else if(')' == input->value && '(' == stack_op->value){
                    stack_pop(&stack_op);
                }else{
                    break;
                }
            }
            if(input->value == ')'){
                stack_pop(&input);
            }else{
              //  printf("%d into op_stack\n",input->value);
                stack_push(stack_pop(&input),&stack_op,1);
            }
        }else{
            stack_push(stack_pop(&input),&output,0);
        }
    }
    while(stack_op != NULL){
        stack_push(stack_pop(&stack_op),&output,1);
    }
    printf("suffix_output:");
    print_stack(output);
    printf("\n");
    while(output != NULL){
        stack_push(stack_pop(&output),output1,output->is_op);
    }
    printf("suffix_output1:");
    print_stack(*output1);
    printf("\n");
    clear_stack(&output);
    return;
}

3.字尾運算

int calculate(stack_t *in_s){
    stack_t *cal_s = stack_init();
    int num1 = 0,num2 = 0;
    while(NULL != in_s){
        if(1 == in_s->is_op){
            num1 = stack_pop(&cal_s);
            num2 = stack_pop(&cal_s);
           // printf("%d %c %d\n",num2,in_s->value,num1);
            switch(in_s->value){
                case '+':
                    stack_push(num2+num1,&cal_s,0);
                    break;
                case '-':
                    stack_push(num2-num1,&cal_s,0);
                    break;
                case '*':
                    stack_push(num2*num1,&cal_s,0);
                    break;
                case '/':
                    stack_push(num2/num1,&cal_s,0);
                    break;
            }
            stack_pop(&in_s);
        }else{
            stack_push(stack_pop(&in_s),&cal_s,in_s->is_op);
        }
    }
    return stack_pop(&cal_s);
}

最後在main()函式裡把字串輸入後轉換入棧，就可以了，記得把輸入的字串入棧處理~
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