计算器源代码 C++（源代码）

#include <iostream> #include <iomanip> #include <cstdlib> #include <cstring> #include <cctype> #include <cmath> using namespace std; const char Tab=0x9; const int DIGIT=1; double fun(double x,char op[],int *iop) { while(op[*iop-1]<32) //本行使得函数嵌套调用时不必加括号 // 如 arc sin(sin(1.234)) 只需键入arc sin sin 1.234<Enter> switch(op[*iop-1]) { case 7: x=sin(x); (*iop)--;break; case 8: x=cos(x); (*iop)--;break; case 9: x=tan(x); (*iop)--;break; case 10: x=sqrt(x); (*iop)--;break; case 11: x=asin(x); (*iop)--;break; case 12: x=acos(x); (*iop)--;break; case 13: x=atan(x); (*iop)--;break; case 14: x=log10(x);(*iop)--;break; case 15: x=log(x); (*iop)--;break; case 16: x=exp(x); (*iop)--;break; } return x; } double calc(char *expr,char **addr) { static deep; static char *fname[]={ "sin","cos","tan","sqrt", "arcsin","arccos","arctan","lg","ln","exp",NULL}; double ST[10]={0.0}; //数字栈 char op[10]={'+'}; //运算符栈 char c,*rexp,*pp,*pf; int ist=1,iop=1,last; if(!deep) { pp=pf=expr; do { c = *pp++; if(c!=' '&& c!=Tab) *pf++ = c; } while(c!='\0'); } pp=expr; if((c=*pp)=='-'||c=='+') { op[0] = c; pp++; } last = !DIGIT; while((c=*pp)!='\0') { if(c=='(')//左圆括弧 { deep++; ST[ist++]=calc(++pp,addr); deep--; ST[ist-1]=fun(ST[ist-1],op,&iop); pp = *addr; last = DIGIT; if(*pp == '('||isalpha(*pp) && strnicmp(pp,"Pi",2)) { ////目的是：当右圆括弧的 op[iop++]='*'; ////右恻为左圆括弧或函数 last = !DIGIT; ////名字时，默认其为乘法 c = op[--iop]; ///////////////////////////// goto operate ; ///////////////////////////// } } else if(c==')')//右圆括弧 { pp++; break; } else if(isalpha(c)) { if(!strnicmp(pp,"Pi",2)) { if(last==DIGIT){cout<< "π左侧遇）" <<endl;exit(1);} ST[ist++]=3.14159265358979323846; ST[ist-1]=fun(ST[ist-1],op,&iop); pp += 2; last = DIGIT; if(!strnicmp(pp,"Pi",2)){cout<< "两个π相连" <<endl;exit(2);} if(*pp=='('){cout<< "π右侧遇（" <<endl;exit(3);} } else { for(int i=0; (pf=fname[i])!=NULL; i++) if(!strnicmp(pp,pf,strlen(pf)))break; if(pf!=NULL) { op[iop++] = 07+i; pp += strlen(pf); } else {cout<< "陌生函数名" <<endl;exit(4);} } } else if(c=='+'||c=='-'||c=='*'||c=='/'||c=='^') { char cc; if(last != DIGIT){cout<< "运算符粘连" <<endl;exit(5);} pp++; if(c=='+'||c=='-') { do { cc = op[--iop]; --ist; switch(cc) { case '+': ST[ist-1] += ST[ist];break; case '-': ST[ist-1] -= ST[ist];break; case '*': ST[ist-1] *= ST[ist];break; case '/': ST[ist-1] /= ST[ist];break; case '^': ST[ist-1] = pow(ST[ist-1],ST[ist]);break; } } while(iop); op[iop++] = c; } else if(c=='*'||c=='/') { operate: cc = op[iop-1]; if(cc=='+'||cc=='-') { op[iop++] = c; } else { --ist; op[iop-1] = c; switch(cc) { case '*': ST[ist-1] *= ST[ist];break; case '/': ST[ist-1] /= ST[ist];break; case '^': ST[ist-1] = pow(ST[ist-1],ST[ist]);break; } } } else { cc = op[iop-1]; if(cc=='^'){cout<< "乘幂符连用" <<endl;exit(6);} op[iop++] = c; } last = !DIGIT; } else { if(last == DIGIT){cout<< "两数字粘连" <<endl;exit(7);} ST[ist++]=strtod(pp,&rexp); ST[ist-1]=fun(ST[ist-1],op,&iop); if(pp == rexp){cout<< "非法字符" <<endl;exit(8);} pp = rexp; last = DIGIT; if(*pp == '('||isalpha(*pp)) { op[iop++]='*'; last = !DIGIT; c = op[--iop]; ///////////////////////////// goto operate ; ///////////////////////////// } } } *addr=pp; if(iop>=ist){cout<< "表达式有误" <<endl;exit(9);} while(iop) { --ist; switch(op[--iop]) { case '+': ST[ist-1] += ST[ist];break; case '-': ST[ist-1] -= ST[ist];break; case '*': ST[ist-1] *= ST[ist];break; case '/': ST[ist-1] /= ST[ist];break; case '^': ST[ist-1] = pow(ST[ist-1],ST[ist]);break; } } return ST[0]; } int main() { char s[128],*end; system("chcp 936"); //中文代码页 while(1) { cout << "请输入表达式："; cin.getline(s,128); cout << setprecision(17) << calc(s,&end) << endl; } return 0;