|
im having a problem here.. my program always output Invalid Gender! after I input the gender and status..
#include stdio.h>
/*Ambus*/
int main()
{
char stat[10], gend[10];
int rCTR, mmCTR, fsCTR;
clrscr(); mmCTR = 0; fsCTR = 0;
for (rCTR = 1; rCTR <= 10; rCTR++)
{
JJ:printf("\n Record %d \n",rCTR);
printf("Input your gender:"); scanf("%s",&gend);
printf("Input your civil status:"); scanf("%s",&stat);
if(gend == "female")
{
if(stat == "single")
fsCTR++;
else if(stat == "married");
else
{
printf("Invalid civil status!");
goto JJ;
}
}
else if(gend == "male")
{
if(stat == "married")
mmCTR++;
else if(stat == "single");
else
{
printf("Invalid civil status!");
goto JJ;
}
}
else
{
printf("Invalid gender!");
goto JJ;
}
}
printf("Single females=%d, Married males=%d, Number of Records=%d.", mmCTR, fsCTR, rCTR-1);
return 0;
}
|
|
|
|
|
if(gend == "female")
That is not a valid way to compare strings in C. You need to use one of the string compare functions: see strcmp, wcscmp, _mbscmp[^]. It is also a bad idea to use the goto statement, use loops instead.
|
|
|
|
|
You are comparing a character array (a pointer) with a pointer to a constant string:
if(gend == "female")
Those pointers will never be identical.
If you want to compare strings (the content pointed to by the pointers), you must compare each element (character) of the strings. There is the strcmp[^] C standard library function to do this:
if (!strcmp(gend, "female")) 
|
|
|
|
|
ohh.. i see.. thank you very much :3
|
|
|
|
|
I wonder: what IDE / compiler are you using? Isn't the debugging possible? 
|
|
|
|
|
it is possible.. btw im just a beginner :3
|
|
|
|
|
This is very interesting. Thanks for your support. Getting a wonderful experience. With best compliments.
Shiv Prakash
|
|
|
|
|
I have an application in Visual C++ 6.0, but I need to send an arrangement of bytes to another computer through a net cable, using socket. Please that somebody please tells me how to make it or that they show me an example.
|
|
|
|
|
Plenty of example out there on the web. Did you look?
Search[^]
|
|
|
|
|
|
Hello,
Could you please provide some examples "
In C++ compiler providing the default copy constructor ,then why do we need copy constructor . "
Thanks and Regards,
Ranjithkumar.S
ranjith
|
|
|
|
|
When you want something other than the default behavior.
|
|
|
|
|
provide some example
ranjith
|
|
|
|
|
If this was a write code to order service, what sort of an example would I write for you? But since this is not a coding service, no, I won't do your homework for you.
|
|
|
|
|
|
Copy constructors - cppreference.com[^]
Default Copy Constructor - C++ Forum[^]
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles
|
|
|
|
|
Basically when you need custom logic in copying. For example, dynamic memory allocation in pointer members.
Same thing is applicable in assignment operator overloading too.
|
|
|
|
|
There are tons of examples out there, here is but one[^].
"the debugger doesn't tell me anything because this code compiles just fine" - random QA comment
"Facebook is where you tell lies to your friends. Twitter is where you tell the truth to strangers." - chriselst
"I don't drink any more... then again, I don't drink any less." - Mike Mullikins uncle
|
|
|
|
|
May be it is orthogonal information, If we want to hide/restrict usage of default copy constructor, we need to provide override declaration in private section of class, and no definition for that. This ensures preventing usages of copy constructor
|
|
|
|
|
I have read a lot of stuf of programmers triying to swap arrays using for over every element like here (two pages):
[^]
There also other methods that involves making swapping element by element but it is hidden:
std::swap(array1,array2);
It would be better using pointers, with only 3 operations all the elements are swapped:
double *a,*b; two arrays
double **ptr1,**ptr2,**ptrx;
ptr1=&a;ptr2=&b;
Swapping:
ptrx=ptr1;ptr1=ptr2;ptr2=ptrx;
Example code:
<pre lang="c++">
#include <iostream>
using namespace std;
double *a;
double *b;
class c_class { public: double x; } ;
void main()
{
a = new double[7];
b = new double[7];
long i;
for (i = 0; i < 7; i++)
{
a[i] = i + 100;
b[i] = i + 300;
}
double **ptr1 = &a,**ptr2=&b,**ptrx;
cout << "=== SWAPPING ARRAYS ===" << endl;
cout << "STEP 1: ptr1= " << endl;
for (i = 0; i < 7; i++) cout << (*ptr1)[i] << " ";
cout << " ptr2= ";
for (i = 0; i < 7; i++) cout << (*ptr2)[i] << " ";
cout << endl;
cout << " Swapping the arrays" << endl;
ptrx = ptr1; ptr1 = ptr2; ptr2 = ptrx;
cout << "STEP 2: ptr1= ";
for (i = 0; i < 7; i++) cout << (*ptr1)[i] << " ";
cout << " ptr2= ";
for (i = 0; i < 7; i++) cout << (*ptr2)[i] << " ";
cout << endl;
cout << " Swapping the arrays" << endl;
ptrx = ptr1; ptr1 = ptr2; ptr2 = ptrx;
cout << "STEP 3: ptr1= ";
for (i = 0; i < 7; i++) cout << (*ptr1)[i] << " ";
cout << " ptr2= ";
for (i = 0; i < 7; i++) cout << (*ptr2)[i] << " ";
cout << endl;
cout << "\n\n=== SWAPPING CLASSES ==="<<endl;
c_class clas1, clas2;
clas1.x = 1000.1;
clas2.x = 5000.5;
c_class *pc1, *pc2,*pcx;
pc1 = &clas1; pc2 = &clas2;
cout << "Class 1 and 2 x value: " << pc1->x << " "<<pc2->x<<endl;
cout << " Swapping the classes " << endl;
pcx = pc1; pc1 = pc2; pc2 = pcx;
cout << "Class 1 and 2 x value: " << pc1->x << " " << pc2->x << endl;
cout << "\n\n======end========\n"; getchar(); getchar();
The only problem is that the arrays must be declared initially as pointers. If they are declared as:
double a[7];, the vs2013 does mark pointer assigment as an error:
double *ptr=a;
Is there a way to solve it?
|
|
|
|
|
All you are doing there is changing the pointers, which makes no real sense. What problem are you trying to solve?
|
|
|
|
|
Given his code it will be a sort routine like bubble sort, but it looks like homework to me so I am reluctant.
Usually they are asked to do an in place array sort and it. He hasn't worked out how to typecast the pointers properly and it seems to escape him that you can just malloc the arrays which is what his "new" statement hides.
In vino veritas
modified 20-Sep-16 6:53am.
|
|
|
|
|
The idea is use the pointers to avoid copying all the data.
An example, if there are 3 arrays of pixels: A, B, C and I want to order the arrays I can make the following operation:
if (distance(A,B)>distance(A,C))
swap(B,C);
I tried this code that swaps anything but it does not compile:
#include <iostream>
#include <string>
using namespace std;
void swap(void *&a,void *&b)
{
void *x=a;a=b;b=x;
}
void main()
{
int a[3]={100,101,102};
int b[3]={200,201,202};
cout << "a:"<<a[0]<<" "<<a[1]<<" "<<a[2]<<endl;
cout << "b:"<<b[0]<<" "<<b[1]<<" "<<b[2]<<endl;
swap((void *) a,(void *) b);
cout << "a:"<<a[0]<<" "<<a[1]<<" "<<a[2]<<endl;
cout << "b:"<<b[0]<<" "<<b[1]<<" "<<b[2]<<endl;
cout << "=== END ===" << endl; getchar();
}
modified 18-Aug-17 5:26am.
|
|
|
|
|
Why are you using void* in your swap method and calls? Void pointers do not point to anything so the compiler cannot figure out what to do. Since both arrays are of int type, then that is the type of pointer you should be using. Also your swap method does not make much sense, again you are swapping pointers not data.
|
|
|
|
|
Because I would like to swap pointers, not to copy all the data. If I swap 2 arrays of 1k size using pointers is 1000x times faster than copying all the data.
This code do it using void * pointers (but I do not know if it could work in other SO), so the next step is to place it in a function:
int a[3]={100,101,102};
int b[3]={200,201,202};
void *x;int *a1=a,*b1=b;
x=(void *) a1;a1=b1;b1=(int *) x;
cout << "a:"<<a1[0]<<" "<<a1[1]<<" "<<a1[2]<<endl;
cout << "b:"<<b1[0]<<" "<<b1[1]<<" "<<b1[2]<<endl;
I tried this function using C++11 and seems to work:
template<class A>
void swap(A *&a,A *&b)
{
A *x=a;a=b;b=x;
}
void main()
{
int a[3]={100,101,102};
int b[3]={200,201,202};
int *a1=a,*b1=b;
swap(a1,b1);
cout << "a:"<<a1[0]<<" "<<a1[1]<<" "<<a1[2]<<endl;
cout << "b:"<<b1[0]<<" "<<b1[1]<<" "<<b1[2]<<endl;
}
Unfortunately I cannot call swap using a and b:
swap(a,b)
modified 21-Aug-17 3:52am.
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
