如不清楚算法思路，请点下方的链接：
算法思路
#include<stdio.h>#include<stdlib.h>/*数据栈*/struct shuju {int data[100];int top;};/*符号栈*/ struct fuhao {char symbol[100];int top;};void InitOperateNum(struct shuju *StackNum) {StackNum->top = -1;}void InitOperateSymbol(struct fuhao *StackSymbol) {StackSymbol->top = -1; }/*存入数据栈*/void Inshuju(struct shuju *StackNum, int num){StackNum->top ++;StackNum->data[StackNum->top] = num;}/*存入符号栈*/ void Infuhao(struct fuhao *StackSymbol, char ch){StackSymbol->top ++;StackSymbol->symbol[StackSymbol->top] = ch;}/*读取数据栈*/int Randshuju(struct shuju *StackNum){return StackNum->data[StackNum->top];}/*读取符号栈*/char Randfuhao(struct fuhao *StackSymbol){return StackSymbol->symbol[StackSymbol->top];}/*从数据栈取出数据*/int Putshuju(struct shuju *StackNum){int x;x = StackNum->data[StackNum->top];StackNum->top --;return x;}/*从符号栈取出符号*/char Putfuhao(struct fuhao *StackSymbol){char c;c = StackSymbol->symbol[StackSymbol->top];StackSymbol->top --;return c;}/*符号优先级判断*/int judge(char ch) {if(ch == '(') {return 1; }if(ch == '+' || ch == '-') {return 2;}else if(ch == '*' || ch == '/') {return 3;}else if(ch == ')') {return 4;}}/*四则运算*/int Math(int v1, int v2, char c){int sum;switch(c) {case '+' : {sum = v1 + v2;break;}case '-' : {sum = v1 - v2;break;}case '*' : {sum = v1 * v2;break;} case '/' : {sum = v1 / v2;break;}}return sum;}int main(){struct shuju data;struct fuhao symbol;InitOperateNum(&data);InitOperateSymbol(&symbol);int i, t, sum, v1, v2;char c;i = t = sum = 0;char v[100] = {0};char *str = (char *)malloc(sizeof(char)*200);while((c = getchar()) != '\n') {str[i] = c;i ++;}str[i] = '\0';for(i = 0; str[i] != '\0'; i ++) {if(i == 0 && str[i] == '-') {v[t++] = str[i];}else if(str[i] == '(' && str[i+1] == '-') {i ++;v[t++] = str[i++];while(str[i] >= '0' && str[i] <= '9') {v[t] = str[i];t ++;i ++;}Inshuju(&data, atoi(v));while(t > 0) {v[t] = 0;t --;}if(str[i] != ')') {i --;Infuhao(&symbol, '(');}}else if(str[i] >= '0' && str[i] <= '9') {while(str[i] >= '0' && str[i] <= '9') {v[t] = str[i];t ++;i ++;}Inshuju(&data, atoi(v));while(t > 0) {v[t] = 0;t --;}i --;}else {if(symbol.top == -1) {//如果符号栈没有元素，直接把符号放入符号栈 Infuhao(&symbol, str[i]);}else if(judge(str[i]) == 1) {//如果此符号是'('，直接放入符号栈 Infuhao(&symbol, str[i]);}else if(judge(str[i]) == 2) {//如果此符号是'+'或'-'，判断与栈顶符号是优先级 if(judge(Randfuhao(&symbol)) == 1) {//如果栈顶符号是'('，放入符号栈 Infuhao(&symbol, str[i]);}else if(judge(Randfuhao(&symbol)) == 2) {//如果栈顶符号是'+'或'-'，则出栈运算 while(symbol.top >= 0 && data.top >= 1) {//循环出栈v2 = Putshuju(&data);v1 = Putshuju(&data);sum = Math(v1, v2, Putfuhao(&symbol));Inshuju(&data, sum); //将运算结果压入数据栈 }Infuhao(&symbol, str[i]); //新符号进栈 }else if(judge(Randfuhao(&symbol)) == 3) {//如果栈顶符号是'*'或'/'，则进符号栈 while(symbol.top >= 0 && data.top >= 1) {//循环出栈v2 = Putshuju(&data);v1 = Putshuju(&data);sum = Math(v1, v2, Putfuhao(&symbol));Inshuju(&data, sum); //将运算结果压入数据栈 }Infuhao(&symbol, str[i]); //新符号进栈 }/*栈顶符号不可能是')'，故不做判断*/ }else if(judge(str[i]) == 3) {//如果此符号是'*'或'/'，则判断与栈顶符号是优先级if(judge(Randfuhao(&symbol)) == 1) {//如果栈顶符号是'('，放入符号栈 Infuhao(&symbol, str[i]);}else if(judge(Randfuhao(&symbol)) == 2) {//如果栈顶符号是'+'或'-'，则进符号栈Infuhao(&symbol, str[i]); //新符号进栈}else if(judge(Randfuhao(&symbol)) == 3) {//如果栈顶符号是'*'或'/'，则出栈运算 while(symbol.top >= 0 && data.top >= 1) {//循环出栈v2 = Putshuju(&data);v1 = Putshuju(&data);sum = Math(v1, v2, Putfuhao(&symbol));Inshuju(&data, sum); //将运算结果压入数据栈 }Infuhao(&symbol, str[i]); //新符号进栈}}else if(judge(str[i]) == 4) {// 如果此符号是')'，则出栈运算直到遇到'('do {//循环出栈直到遇到'('v2 = Putshuju(&data);v1 = Putshuju(&data);sum = Math(v1, v2, Putfuhao(&symbol));Inshuju(&data, sum); //将运算结果压入数据栈 }while(judge(Randfuhao(&symbol)) != 1);Putfuhao(&symbol); //括号内运算结束后使'('出栈 } }}free(str); //释放内存空间while(symbol.top != -1) {v2 = Putshuju(&data);v1 = Putshuju(&data);sum = Math(v1, v2, Putfuhao(&symbol));Inshuju(&data, sum);}printf("%d", data.data[0]);return 0;}
