编程析取范式求主析取范式。。



离散数学中析取范式如何通过计算机求主析取范式。其中一种办法就是用二维数组存储析取范式的真值表，然后代入命题公式，真值为T，就是它的最小项。其中会用到栈这种数据结构判断优先级。。

#include<iostream>#include <cstdio>  #include <cstdlib>#include <string>using namespace std;template<class T>class stack{private:int top;T *atr;int maxize;public:stack(int size=0);~stack();bool IsFull();bool IsEmpty();void pop(T &item);void push(T &item);void clear();void GetTop(T &item);};class calculator{private:int number;int iN;string thz;char* min;int **p;string st1;public:calculator();~calculator();void TheMin();void show();};template<class T>stack<T>::stack(int size=0){maxize = size;atr = new T[maxize];top = -1;}template<class T>stack<T>::~stack(){delete[]atr;}template<class T>bool stack<T>::IsFull(){return top ==maxize - 1;}template<class T>bool stack<T>::IsEmpty(){return top== -1;}template<class T>void stack<T>::clear(){top == -1;}template<class T>void stack<T>::pop(T &item){item = atr[top--];}template<class T>void stack<T>::push(T &item){atr[++top] = item;}template<class T>void stack<T>::GetTop(T &item){item = atr[top];}calculator::calculator(){char p[100], c = '\0',a='\0';stack <char> s(10);int i = 0;number = 0;cout << "输入*表示合取，+表示析取，！表示非，记得输入大写字母的命题变员" << endl;while (1){c = getchar();if (c == '\n')break;p[i++] = c;}for (int j = 0; j < i; j++){if (p[j] >= 'A'&&p[j] <= 'Z'){thz += p[j];int k = 0;for (;st1[k];k++){if (p[j] == st1[k])break;}if (!st1[k]){st1 += p[j];number++;}}else if (p[j] == '+' || p[j] == '*' || p[j] == '!'||p[j]=='('){s.GetTop(c);if (s.IsEmpty()||p[j]=='!'||p[j] == '('){s.push(p[j]);}else if (p[j] == '*'&&(c=='*'||c=='!')){s.pop(a);thz += a;s.push(p[j]);}else if (p[j] == '+'&&!s.IsEmpty() && c != '('){s.pop(a);thz += a;s.push(p[j]);}else if (c == '(')s.push(p[j]);}else if (p[j] == ')'){if (!s.IsEmpty()){while (!s.IsEmpty()){s.pop(a);if (a == '(')break;thz += a;}if (a != '('){cout << "能不能输入正确呀!" << endl;return ;}}else{cout << "哈哈哈，你又错了!" << endl;return;}}}while (!s.IsEmpty()){s.pop(a);thz += a;}}calculator::~calculator(){    for (int i = 0; i < iN; i++){delete[]p[i];}delete []p;}void calculator::TheMin(){stack<int> s1(20);min = new char[100];int a, b,c=0,d=1,t=0;iN = pow(2, number);int count = number;p = new int*[iN];for (int i = 0; i < iN; i++){p[i] =new int[number];}for (int i = 0; i < iN; i++){for (int j = count - 1, k = i; j >= 0; j--){p[i][j] = k % 2;k = k / 2;}}int k = 0;for (; k<iN; k++){for (int j = 0;thz[j]; j++){if (thz[j] >= 'A'&&thz[j] <= 'Z'){int e = 0;for (; st1[e]; e++){if (thz[j] == st1[e])break;}s1.push(p[k][e]);}else if (thz[j] == '!'){s1.pop(a);if (a == 1)s1.push(c);elses1.push(d);}else if (thz[j]=='*'){s1.pop(a);s1.pop(b);if (a == 1 && b == 1)s1.push(d);elses1.push(c);}else{s1.pop(a);s1.pop(b);if (a == 0 && b == 0)s1.push(c);elses1.push(d);}}        s1.pop(a);if (a == 1){for (int f = 0; f < number; f++){if (p[k][f] == 0){min[t++]= '!';min[t++]= st1[f];}if (p[k][f] == 1)min[t++]= st1[f];if (f != number - 1)min [t++]= '*';}min[t++]= '+';}}min[t] = '\0';for (int i = 0; i<t-1; i++){cout << min[i];}}int main(){calculator c;c.TheMin();}