problem with c++

please tell me what's wrong with the program
thx.

Code:

#include<iostream> #include<cmath> #include<fstream> using namespace std; void menu(); void fuc1(); void fuc2(); double calculate(double); int main() { char choice; menu(); cout<<"Enter choice: "; cin>>choice; if(choice=='+'||'-'||'*'||'/'||'%'||'P'||'A'||'X') fuc1(); else if(choice=='R'||'F'||'T') fuc2(); else exit; system("pause"); return 0; } void menu() { cout<<"+,-,*,/,%"<<endl; cout<<"A\t averge"<<endl; cout<<"X\t maximum"<<endl; cout<<"P\t a^b"<<endl; cout<<"R\t reciprocal"<<endl; cout<<"F\t factorial"<<endl; cout<<"T\t square root"<<endl; cout<<"Q\t quit"<<endl; } void fuc1() { int operand1,operand2,result; char choice; cout<<"Enter two values you want to calculate: "; cin>>operand1 >>operand2; if(choice=='+') result=operand1+operand2; if(choice=='-') result=operand1-operand2; if(choice=='*') result=operand1*operand2; if(choice=='/') result=operand1/operand2; if(choice=='%') result=operand1%operand2; if(choice=='P') result=pow((double)operand1,(double)operand2); if(choice=='A') result=(operand1+operand2)/2; else if(operand1>operand2) result=operand1; else result=operand2; cout<<choice<<" "<<result<<" "<<operand1<<" "<<operand2<<endl; } void fuc2() { double operand1,result; char choice; cout<<"Enter one value you want to calculate: "; cin>>operand1; calculate(operand1); cout<<choice<<" "<<result<<" "<<operand1<<endl; } double calculate(double x) { char choice; double result; if(choice=='R') result=1/x; else if(choice=='F') for(int i=1;i<=x;i++) result*=i; else result=sqrt(x); return result; }

it did not print out the choice and the right answer

Code:

if(x == 1 || 2)

is not the same as

Code:

if(x == 1 || x == 2)

I tried it also, but still not working correctly

Quote:

Originally Posted by wind0

I tried it also, but still not working correctly

show the latest code and explain what do you mean by "not working correctly": what input you give, what output you get, what output you expect

when i chose '+', i entered 2 and 5, it should print out + 7 2 5.
but what i got was 5 2 5, no + and wrong result

Please post your corrected code.

Quote:

I tried it also, but still not working correctly

Seems you have a trial on error point of view to it. When you program in C/C++ you should exactly know what you are doing. (Just trying to give a better point of view.)

Code:

void fuc1() { int operand1,operand2,result; char choice; // choice declared here cout<<"Enter two values you want to calculate: "; cin>>operand1 >>operand2; if(choice=='+') // What is the value of choice here?

See comments in code.

i declared choice also in main, how should it be known in fuc?

OK this is what i did, thx to rags_to_riches
I got the choice print, but the result is still incorrect.

Code:

#include<iostream> #include<cmath> #include<fstream> using namespace std; void menu(); void fuc1(char); void fuc2(char); double calculate(char,double); int main() { char x; menu(); cout<<"Enter choice: "; cin>>x; if(x=='+'||x=='-'||x=='*'||x=='/'||x=='%'||x=='P'||x=='A'||x=='X') fuc1(x); else if(x=='R'||x=='F'||x=='T') fuc2(x); else exit; system("pause"); return 0; } void menu() { cout<<"+,-,*,/,%"<<endl; cout<<"A\t averge"<<endl; cout<<"X\t maximum"<<endl; cout<<"P\t a^b"<<endl; cout<<"R\t reciprocal"<<endl; cout<<"F\t factorial"<<endl; cout<<"T\t square root"<<endl; cout<<"Q\t quit"<<endl; } void fuc1(char choice) { int operand1,operand2,result; cout<<"Enter two values you want to calculate: "; cin>>operand1 >>operand2; if(choice=='+') result=operand1+operand2; if(choice=='-') result=operand1-operand2; if(choice=='*') result=operand1*operand2; if(choice=='/') result=operand1/operand2; if(choice=='%') result=operand1%operand2; if(choice=='P') result=pow((double)operand1,(double)operand2); if(choice=='A') result=(operand1+operand2)/2; else if(operand1>operand2) result=operand1; else result=operand2; cout<<choice<<" "<<result<<" "<<operand1<<" "<<operand2<<endl; } void fuc2(char choice) { double operand1,result; cout<<"Enter one value you want to calculate: "; cin>>operand1; calculate(choice,operand1); cout<<choice<<" "<<result<<" "<<operand1<<endl; } double calculate(char choice,double x) { double result; if(choice=='R') result=1/x; else if(choice=='F') for(int i=1;i<=x;i++) result*=i; else result=sqrt(x); return result; }

Code:

if(choice=='+') result=operand1+operand2; if(choice=='-') result=operand1-operand2; if(choice=='*') result=operand1*operand2; if(choice=='/') result=operand1/operand2; if(choice=='%') result=operand1%operand2; if(choice=='P') result=pow((double)operand1,(double)operand2); if(choice=='A') //Last if black result=(operand1+operand2)/2; else if(operand1>operand2) result=operand1; else result=operand2;

It has a problem. Because you didn't use "else if" instead of a new if, all the conditions are checked even though we know only one will be true and when one is true all the others will be false. It also leads to another problem. The last "if" is always evaluated and in conditions that choice is not 'A' its else block is always executed. So your result will always be operand1 or operand2. Use switch statement instead of an if block to make the code easier to read.

Code:

else exit;

This should be exit() to call the function (your compiler should already has generated a warning about this).