C语⾔实现简易计算器（可作加减乘除）C语⾔实现简易计算器（加减乘除）计算器作为课设项⽬，已完成答辩，先将代码和思路（注释中）上传⼀篇博客已增添、修改、整理⾄⽆错且可正常运⾏虽使⽤了栈，但初学者可在初步了解栈和结构语法后理解代码#include <stdlib.h>#include <stdio.h>#include <string.h>#define IsDouble 0#define IsChar 1//_______________________________________________________________________________________________________________________________________________________ //1.⽀持浮点数和字符的栈typedef struct {char * buffer;int typesize;int top;int max;} stack;stack * CreateStack(int max, int typesize);//创建⼀个栈void DestroyStack(stack *);//释放栈的空间void ClearStack(stack *);//清空栈int Push(stack *, void *);//⼊栈int Pop(stack *, void *);//出栈int GetSize(stack *s);//得到栈的⼤⼩int GetTop(stack *, void *);//找到栈顶int IsEmpty(stack *);//判断是否为空栈，空则下溢int IsFull(stack *);//判断栈是否已满，满则溢出stack * CreateStack(int max, int typesize){stack * s = (stack*)malloc(sizeof(stack));//为栈s malloc内存if (!s) return 0;//为结构中buffer元素malloc内存s->buffer = (char *)malloc(sizeof(char) * max * typesize);if (!s->buffer) return 0;//初始化结构中的栈顶，最⼤值，类型⼤⼩s->top = -1;s->max = max;s->typesize = typesize;return s;}void DestroyStack(stack* s){free(s->buffer);//先释放buffer的空间free(s);//在释放s的空间}void ClearStack(stack * s){s->top = -1;//清空栈(栈头位置归零)}int Push(stack * s, void * data){if (IsFull(s)) return 0;//如果栈已满则return 0，防⽌溢出//栈未满则将栈头移动打动下⼀位置，并将data中的元素拷⼊栈中buffer的第top位置s->top++;memcpy(s->buffer + s->top*s->typesize, data, s->typesize);//⼊栈成功return 1return 1;}int Pop(stack * s, void * data){if (IsEmpty(s)) return 0;//出栈判断栈是否为空，若为空则return 0//栈未空则将buffer中top位置的字符拷⼊data记录，并让栈头向前移动⼀个位置memcpy(data, s->buffer + s->top*s->typesize, s->typesize);s->top--;//成功则return 1return 1;}int GetSize(stack *s){return s -> top+1;//栈头位置+1得到⼤⼩}int GetTop(stack *s, void * data){if (IsEmpty(s)) return 0;//如果栈空return 0//栈不为空则将top位置的字符拷回data记录，得到栈头memcpy(data, s->buffer + s->top*s->typesize, s->typesize);//成功则return 1；return 1;}int IsEmpty(stack * s){return s->top == -1;//如果top为-1则栈空}int IsFull(stack * s){return s->top == s->max-1;//如果top为max-1则栈满}//___________________________________________________________________________________________________________________________________________________ //2.定义⼀个cal类型，其中data存数时sign为IsDouble，存字符时，sign为Ischartypedef struct {double data;char sign;} cal;//3.查找对应符号（找到则返回该符号下标）（找不到则说明该部分为数字返回-1）int SearchCode(char ch){char * code = "+-*/()@";//@为终⽌符，算式输⼊结束int index = 0;//while (code[index]){if (code[index] == ch) return index;index++;}return -1;}//4.得到两个符号间的优先级//与SearchCode相对应，char GetPriority(char ch, char next){//创建⼀个perferen表，第i⾏(列)对应SearchCode函数中code中的第i个字符char perferen[7][7] = {">><<<>>",">><<<>>",">>>><>>",">>>><>>","<<<<<=E",">>>>E>>","<<<<<E="};//找到两个形参对应的字符int c = SearchCode(ch);int n = SearchCode(next);//如果找不到对应运算符（字符不是运算符⽽是为数字）return Eif (c==-1 || n==-1) return 'E';//如果找到两个对应运算符则按照优先级表返回两个运算符的优先级return perferen[c][n];}//5.四则运算double add(double a, double b) { return a+b; }double sub(double a, double b) { return a-b; }double mul(double a, double b) { return a*b; }double ddiv(double a, double b) { return a/b; }//整合四种运算double calcu(double a, char ch, double b){double (*calculation[4])(double,double) = {add,sub,mul,ddiv};return calculation[SearchCode(ch)](a,b);}//6.检测字符串int CheckStr(char * buffer){int n;//遍历字符串确保算式中⽆⾮法字符若检测到⾮法字符return 0，若都合法则return 1for (n = 0;buffer[n];n++){if ((SearchCode(buffer[n]) != -1 || buffer[n] == '.' || (buffer[n] >= '0' && buffer[n] <= '9')) && buffer[n] != '@') continue;else return 0;}buffer[n] = '@';//加上终⽌符，表⽰算式结束buffer[n+1] = '\0';return 1;}//7.得到数据转化为double类型存⼊rsint GetDigit(char * buffer, int * n, double * rs){char str[30];int i,j = 0;for (i = 0;SearchCode(buffer[*n]) == -1;i++){str[i] = buffer[*n];//从*n位置开始，将这⼀串数字字符存⼊str(*n)++;}str[i] = '\0';for (i = 0;str[i];i++){if (str[i] == '.') j++;}//如果⼀段⼩数有多个⼩数点或⼩数点在数字⾸尾，return 0if (j>1 || str[i-1] == '.' || str[0] == '.') return 0;//rs接收转化为double的数据*rs = atof(str);//操作成功return 1return 1;}//8.将⽤户输⼊的buffer字符串转化为可供程序运算的calstr数组int resolu(char * buffer, cal * calstr){int i = 0, j = 0;cal c;while (buffer[i]){if (SearchCode(buffer[i]) == -1){//如果得到数据不成功则return 0if (GetDigit(buffer,&i, &c.data) == 0) return 0;//如果成功得到数据则在c.sign标记为浮点数c.sign = IsDouble;//将c存⼊数组calstr中calstr[j++] = c;}else{//若符号为运算符//判断正负号if (buffer[i] == '-' && (buffer[i-1] == '('||buffer[i-1] == '+'||buffer[i-1] == '-'||buffer[i-1] == '*'||buffer[i-1] == '/') || (i==0 && buffer[0] == '-')){ i++;if (GetDigit(buffer,&i, &c.data) == 0) return 0;//在符号的下⼀位开始查找，若找不到数字return 0//否则，给数字取相反数，c.sign标记为浮点数，存⼊calstr中c.data = 0 - c.data;c.sign = IsDouble;calstr[j++] = c;} else//如果是正号，与符号处理⽅式同理if (buffer[i] == '+' && (buffer[i-1] == '('||buffer[i-1] == '+'||buffer[i-1] == '-'||buffer[i-1] == '*'||buffer[i-1] == '/') || (i==0 && buffer[0] == '+')){ i++;if (GetDigit(buffer, &i, &c.data) == 0) return 0;c.sign = IsDouble;calstr[j++] = c;}else{//如果不是正负号，则为运算符，先强制转换为double类型存在c.data⾥，然后c.sign标记为char类型，存⼊calstrc.data = (double)buffer[i++];c.sign = IsChar;calstr[j++] = c;}}}//操作蔡成功则return 1return 1;}//9.计算出结果int result(cal * calstr, double * rs){stack * pst = CreateStack(100,sizeof(char));//运算符栈stack * pnd = CreateStack(100,sizeof(double));//数据栈double num1,num2;int n = 0;char ch = '@';Push(pst, &ch);//在转换得到的calstr中遍历直到终⽌符'@"while(ch != '@' || !(calstr[n].sign == IsChar && (char)calstr[n].data == '@')){//如果calstr的n位上是浮点数，则将这个data压栈进⼊数据栈pnd中if (calstr[n].sign == IsDouble){Push(pnd, &(calstr[n].data));n++;}//反之，如果是运算符，则要检测优先级else{switch( GetPriority(ch, (char)calstr[n].data)){//如果运算符优先级较⼩，则让ch等于优先级⼤的符号并压⼊符号栈pst中case '<':ch = (char)calstr[n].data;Push(pst, &ch);n++;break;//如果结果为等号，让符号出栈暂存到ch中case '=':if (!Pop(pst, &ch)) return 0;n++;break;//如果ch优先级较⾼，则将前两个数字及运算符出栈，分别储存⾄num2，ch，num1中，进⾏运算，得到的结果再次压栈进⼊pnd中 case '>':if (!(Pop(pnd,&num2) && Pop(pst,&ch) && Pop(pnd,&num1))) return 0;num1 = calcu(num1,ch,num2);Push(pnd, &num1);break;//如果符号顺序出错，return 0case 'E':return 0;}}//检测是否可以得到栈顶符号，栈空则return 0if (!GetTop(pst, &ch)) return 0;}//如果栈中得到了最终结果，并且取出pnd中的最终结果到rs，return 1if (GetSize(pnd) == 1 && GetTop(pnd,rs)){DestroyStack(pst);DestroyStack(pnd);return 1;}//否则 return 0else{return 0;}}//10.⽤户交互函数void treatment(){char buffer[100];//⽤户输⼊的字符串（算式）cal calstr[50];//计算⽤的数组double rs = 0;//计算结果printf("Enter your equation:");gets(buffer);//让⽤户输⼊算式buffer//⽤户不输⼊"exit"就不退出while (!(buffer[0]=='e' && buffer[1]=='x' && buffer[2]=='i' && buffer[3]=='t')){//检查buffer中字符君合法，成功将buffer转化为⽤于计算的calstr数组，成功计算出结果存⼊rsif (CheckStr(buffer) && resolu(buffer,calstr) && result(calstr,&rs)){printf("\n%lf\n",rs);}else{printf("\nError!\n");}printf("Enter \"exit\"to quit");printf("\nEnter your equation:");gets(buffer);//再次让⽤户输⼊算式}printf("\nbye\n");}//11.主函数int main(){treatment();}参考⽂献链接如下[参考⽂献]()。
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