C语言实现任意长度多项式计算（非递归，不带括号）

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#define _CRT_SECURE_NO_WARNINGS#include<stdio.h>#include<stdlib.h>#include<malloc.h>#include<string.h>//执行计算过程的子函数double calc(double * pNum, char* pCh, unsigned int a);int main(){double* pNum = NULL;//用于存储数字char* pCh = NULL;//用于存储符号AA:pNum = (double*)malloc(sizeof(double));//分配一个double内存空间pCh = (char*)malloc(sizeof(char));//分配一个char型内存空间scanf("%lf%c", pNum, pCh);unsigned int a = 2;//用于动态内存分配while (*(pCh+a-2) != '=')//只要输入的符号不是‘=’{pNum = (double*)realloc(pNum,a*sizeof(double));//增加一个double型空间pCh = (char*)realloc(pCh,a*sizeof(char));//增加一个char型内存空间scanf("%lf%c", pNum+a-1, pCh+a-1);a++;}//将最后的结果移到输入多项式的等号后面for (unsigned int i = 0; i < a-1; i++){printf("  ");}double value = calc(pNum, pCh, a - 1);//调用计算函数printf("%lf\n\n",value);//输出计算结果free(pNum);//释放内存free(pCh);//释放内存goto AA;//跳回，准备接收下一个多项式system("pause");return 0;}//用于计算多项式double calc(double * pNum, char* pCh, unsigned int a){unsigned i = 0;//先遍历多项式，计算出乘除while (*(pCh + i) != '='){if (*(pCh + i) == '*'){//计算并移位*(pNum + i) = (*(pNum + i)) * (*(pNum + i + 1));*(pCh + i) = *(pCh + i + 1);for (unsigned int j = i + 1; j < a - 1; j++){pNum[j] = pNum[j + 1];pCh[j] = pCh[j + 1];}a--;i--;//用于调试的代码//for (unsigned int i = 0; i < a; i++)//{//printf("%d%c", pNum[i], pCh[i]);//}//printf("\n");}else if (*(pCh + i) == '/'){*(pNum + i) = (*(pNum + i)) / (*(pNum + i + 1));*(pCh + i) = *(pCh + i + 1);for (unsigned int j = i + 1; j < a - 1; j++){pNum[j] = pNum[j + 1];pCh[j] = pCh[j + 1];}a--;i--;////用于调试的代码//for (unsigned int i = 0; i < a; i++)//{//printf("%d%c", pNum[i], pCh[i]);//}//printf("\n");}i++;}i = 0;//再遍历多项式计算加减while (*(pCh + i) != '='){if (*(pCh + i) == '+'){*(pNum + i) = (*(pNum + i)) + (*(pNum + i + 1));*(pCh + i) = *(pCh + i + 1);for (unsigned int j = i + 1; j < a - 1; j++){pNum[j] = pNum[j + 1];pCh[j] = pCh[j + 1];}a--;i--;////用于调试的代码//for (unsigned int i = 0; i < a; i++)//{//printf("%d%c", pNum[i], pCh[i]);//}//printf("\n");}else if (*(pCh + i) == '-'){*(pNum + i) = (*(pNum + i)) - (*(pNum + i + 1));*(pCh + i) = *(pCh + i + 1);for (unsigned int j = i + 1; j < a - 1; j++){pNum[j] = pNum[j + 1];pCh[j] = pCh[j + 1];}a--;i--;////用于调试的代码//for (unsigned int i = 0; i < a; i++)//{//printf("%d%c", pNum[i], pCh[i]);//}//printf("\n");}i++;}return *pNum;//计算的结果存在pNum的第一个内存地址}
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