本文实例为大家分享了C++实现四则混合运算的计算器，供大家参考，具体内容如下

计算器是带括号的四则运算实际上利用的是栈后进先出的原则

转换思想：

#define _CRT_SECURE_NO_WARNINGS 1#include"stdio.h" #include"stdlib.h" #include"string.h" #define maxsize 1024typedef struct{ float data[maxsize]; int top;}Stack1;void Initstack1(Stack1 *S){ S = (Stack1*)malloc(sizeof(Stack1)); S->top = -1;}int Push1(Stack1 *S, float ch){ if (S->top == maxsize - 1) return 0; else { S->top++; S->data[S->top] = ch; return 1; }}//入栈Pushint Pop1(Stack1 *S, float ch){ if (S->top == -1) printf("栈上溢出!\n"); else ch = S->data[S->top]; S->top--; return 1;}//出栈typedef struct{ char data[maxsize]; int top;}Stack2;void Initstack2(Stack2 *S){ S = (Stack2*)malloc(sizeof(Stack2)); S->top = -1;}int Push2(Stack2 *S, char ch){ if (S->top == maxsize - 1) return 0; else { S->top++; S->data[S->top] = ch; return 1; }}//入栈Pushint Pop2(Stack2 *S, char ch){ if (S->top == -1) printf("栈上溢出!\n"); else ch = S->data[S->top]; S->top--; return 1;}//出栈int Comop(char ch) //判断是否是运算符{ switch (ch) { case'+': case'-': case'*': case'/': case'(': case')': case'#': return 1; default: return 0; }}//判断ch是否为运算符char Prior[7][7] ={ // 运算符优先级表 // '+' '-' '*' '/' '(' ')' '#' { '>', '>', '<', '<', '<', '>', '>' }, { '>', '>', '<', '<', '<', '>', '>' }, /*'*'*/{ '>', '>', '>', '>', '<', '>', '>' }, { '>', '>', '>', '>', '<', '>', '>' }, { '<', '<', '<', '<', '<', '=', '< ' }, { '>', '>', '>', '>', ' ', '>', '>' }, { '<', '<', '<', '<', '<', '> ', '=' },};int Opid(char op1){ switch (op1) { case'+':return 0; case'-':return 1; case'*':return 2; case'/':return 3; case'(':return 4; case')':return 5; case'#':return 6; default:return -123456; }}char Precede(char op1, char op2) //优先级比较{ int a, b; a = Opid(op1); b = Opid(op2); return(Prior[a][b]);}float Operation(float a, char op, float b){ switch (op) { case '+': return b + a; case '-': return b - a; case '*': return b * a; case '/': return b / a; default: return -123456; }}void CreateExpression(char *exp){ if (exp == NULL) { exit(1); } scanf("%s", exp);}void TransmitExpression(char *exp, char postexp[]) //中缀表达式转换后缀表达式{ Stack2 FZ; Initstack2(&FZ); int i = 0; char x; FZ.top = -1; Push2(&FZ, '#'); FZ.data[FZ.top] = '#'; while (*exp != '\0') { if (!Comop(*exp)) { while (*exp >= '0'&&*exp <= '9')//读取一个数字串 { postexp[i++] = *exp; exp++; } postexp[i++] = '#'; } else switch (Precede(FZ.data[FZ.top], *exp)) { case'<': Push2(&FZ, *exp); exp++; break; case'=': x = FZ.data[FZ.top]; Pop2(&FZ, x); exp++; break; case'>': postexp[i++] = FZ.data[FZ.top]; x = FZ.data[FZ.top]; Pop2(&FZ, x); break; } } while (FZ.data[FZ.top] != '#') { postexp[i++] = FZ.data[FZ.top]; x = FZ.data[FZ.top]; Pop2(&FZ, x); } postexp[i] = '\0';}float EvaluateExpression(char *postexp) //后缀表达式的计算{ Stack1 SZ; Initstack1(&SZ); float a, b, d; SZ.top = -1; while (*postexp != '\0') { switch (*postexp) { case'+': case'-': case'*': case'/': a = SZ.data[SZ.top]; Pop1(&SZ, a); b = SZ.data[SZ.top]; Pop1(&SZ, b); Push1(&SZ, Operation(a, *postexp, b)); break; default: d = 0; while (*postexp >= '0'&&*postexp <= '9') { d = 10 * d + *postexp - '0'; postexp++; } Push1(&SZ, d); SZ.data[SZ.top] = d; break; } postexp++; } return(SZ.data[SZ.top]);}int Error(char *exp) //错误表达式判断{ int i = 0; while (exp[i] != '\0') { if ( ((exp[i] == '+' || exp[i] == '-' || exp[i] == '*' || exp[i] == '/') && (exp[i + 1] == ')')) || ((exp[i] == '+' || exp[i] == '-' || exp[i] == '*' || exp[i] == '/') && (exp[i - 1] == '(')) || (exp[i] == ')'&&exp[i + 1] == '(') || (exp[i] == '('&&exp[i + 1] == ')') || ((exp[i] == ')') && exp[i + 1] >= '0'&&exp[i + 1] <= '9') || (exp[i] >= '0'&&exp[i] <= '9'&&exp[i + 1] == '(') || (exp[0] == '+' || exp[0] == '-' || exp[0] == '*' || exp[0] == '/' || exp[0] == ')') || ((exp[i] == '+' || exp[i] == '-' || exp[i] == '*' || exp[i] == '/') && (exp[i + 1] == '+' || exp[i + 1] == '-' || exp[i + 1] == '*' || exp[i + 1] == '/')) || (exp[i] == '/'&&exp[i + 1] == '0') ) return 1; else if (exp[i] == '\0') return 0; i++; } return 0;}void menu(){ printf("\t\t--------------------------------------------\n"); printf("\t\t| 计算器 |\n"); printf("\t\t| ---------------- |\n"); printf("\t\t| | | |\n"); printf("\t\t| ---------------- |\n"); printf("\t\t| 1 2 3 + |\n"); printf("\t\t| 4 5 6 - |\n"); printf("\t\t| 7 8 9 * |\n"); printf("\t\t| 0 （ ） / |\n"); printf("\t\t--------------------------------------------\n"); printf("\t\t 请输入你要进行的操作：\n"); printf("\t\t a表达式求值 b清空 c退出\n");}void clear(){ system("cls"); menu();}void Quit(){ system("cls"); exit(1);}void main(){ char c; char exp[maxsize]; char postexp[maxsize] = { 0 }; menu(); while (1) { scanf("%c", &c); switch (c) { case 'a': sr : printf("请输入要计算的表达式:\n"); CreateExpression(exp); if (!Error(exp)) { TransmitExpression(exp, postexp); printf("后缀表达式为：%s\n", postexp); printf("表达式结果为：%s=", exp); printf("%g\n", EvaluateExpression(postexp)); break; } else if (Error(exp)) { printf("您输入的表达式有误！\n"); goto sr;//goto语句在循环体里进行跳转 } case'b': clear(); break; case'c': Quit(); break; } } system("pause");}

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