What is difference (memory allocation or any) between declaring a variable inside or outside the variable
program1:
#include<stdio.h>
int main() {
int i;
for (i=0;i=<100;i++) {
[Code] .....
Difference b/w program1 and program2. Its look both are same. but my compiler shows something difference.
I want to know
prog1.c
#include<stdio.c>
static int c=6;
int main() {
/*code*/
}
prog2.c
#include<stdio.h>
int main(){
static int c=10;
}
what would be the difference between these two program in the fuctioning of static keyword ?
I got the following lines of code from a book. The variable char c is being used here to demonstration local variable declaration.
while(char c = cin.get() != 'q') {
cout << c << " wasn't it" << endl;
if(char x = c == 'a' || c == 'b')
cout << "You typed a or b" << endl;
else
cout << "You typed " << x << endl;
}
It compiles and runs. There are two issues when I try to run it.
1) It seems to loop through two times for every entry. If I insert cin.ignore() just before the closing bracket, it seems to work better.
2) the variable c does not seem to have the character I entered when examined in the if statement.
What is happening with the variable c inside the while loop scope?
Does c actually get initialized?
I read that Memory is allocated during definition of a variable and not during declaration. Declaration is something like,
Code: int x;
And definition is assigning some value to it. This is what my professor taught. My doubt is if memory is not allocated during declaration, then how the compiler successfully compiles and runs the following, which i had already tried.
Code:
#include<stdio.h>
#include<conio.h>
int main() {
int c;
int *p=&c;
printf("%x",p);
getch();
return 0;
}
The variable c is only declared. But the program outputs a memory address. Shouldn't it show an error?
If i declare 2 variables like this static int first, second; will both of them be declared static or will only first be declared static and second a regular variable?
View 5 Replies View Related#include<iostream>
#include<conio.h>
#include<string>
using namespace std;
class ir;
class Bank_acc {
private:
string name,type,s;
long int accno,temp,balance,in;
[Code]....
errors are:
|6|error: forward declaration of 'class ir'|
|54|error: invalid use of incomplete type 'class ir'|
|99|error: no matching function for call to 'ir::interest()'|
Why I take warning on this code :
Code:
#include<stdio.h>
extern int v = 0; // Declaration and definition of an external
int main(void)
[code]...
Is there any error? Why I take a warning: 'v' initialized and declared 'extern'|||=== Build finished: 0 errors, 1 warnings ===| ???
and what is the meaning of :An extern declaration that initializes a variable serves as a definition of the variable. This rule prevents multiple extern declarations from initializing a variable in different ways.
#include <stdio.h>
#include <math.h>
main() {
int n;
int k;
int j;
//gets user input for length of string
printf("Enter the value of n:");
scanf("%d", &n);
[code]......
When I compile my code I get an error saying that I need declaration specifiers in my is_prime subroutine in the for loop.
Here is the line of code it references.
for(j = 2; j < k; j++)
Code:
#include <iostream>
using namespace std;
void f() {
int x=17;
//cout<<main::y<<endl; i want to access y from main scope
}
int main() {
int y=23;
//cout<<f::x<<endl;
I want to access x from f scope is there any way for this without global declaration? specially about function scopes...
(while)
T minus 10 and counting
T minus 9 and counting
T minus 8 and counting
T minus 7 and counting
T minus 6 and counting
T minus 5 and counting
T minus 4 and counting
T minus 3 and counting
T minus 2 and counting
T minus 1 and counting
Declare the following index before the while loop:
int index = 10;
Correctly code a while statement below using the variable index as defined above, to produce the output shown above.
So this is what my code looks like... I also have to convert this same loop into a do while and for loop. So if I can get this one right I think the others should come relatively easy.
while (int index >= 10) {
cout << "T minus " << index;
index--;
}
im doing a program to store name, age, time and fitness. and i need to hold a table of 5 such records.can i do this?
#include <iostream>
using namespace std;
int name1, age1, time1, fitness1;
int name2, age2, time2, fitness2;
int name3, age3, time3, fitness3;
int name4, age4, time4, fitness4;
int name5, age5, time5, fitness5;
[code].....
Here is the code,
Code:
class A {
};
A& CreateObject() {
static A a;
return a;
} static A aa;
int main() {
return 0;
}
So is there any difference between a defined in CreateObject and aa?
I have this error while compiling the program.
Below is the code :
#include<stdio.h>
#include<stdlib.h>
int main() {
char* A = 0;
char* tmp = 0;
[Code] ....
When a declare a string e.g.
Code:
char str[30]; as a global variable, the srting is initialized to NULL.
But if I declare char str1[30] INSIDE main(), then the string has garbage inside.... Why this happens??
E.g. the following code snippet...
Code:
#include <stdio.h>
char str[50];
int main(){
char str1[50];
[Code] ....
I wrote the following program to initialize a string after the variables is declared, but it isn't working. A warning is given by the compiler, and the execution of the program shows a strange string. How do I initialize variable word in a separate statement from its declaration?
Code:
#include <stdio.h>
int main( void )
{
char word[20];
*word = "Hello";
printf( "The string is %s.
", word );
return 0;
}
I'm having to do a little c++ (coming from java) and don't understand the syntax of the following declaration
Code:
SensorBase* const sensor(mSensors[i]);
It looks like it's declaring a const pointer to a SensorBase object but I don't understand how that applies to sensor(mSensors[i]) which looks like a function??
I am getting a compilation error from the code below. It is when i am naming a variable with my user defined type.
#include<iostream>
#include<cstring>
#include<cstdlib>
using namespace std;
class person {
[Code] .....
C:Dev-CppTRIAL.PASS.!!!.cpp In function `int main()':
66 C:Dev-CppTRIAL.PASS.!!!.cpp expected primary-expression before "p"
66 C:Dev-CppTRIAL.PASS.!!!.cpp expected `;' before "p"
74 C:Dev-CppTRIAL.PASS.!!!.cpp `p' undeclared (first use this function)
(Each undeclared identifier is reported only once for each function it appears in.)
83 C:Dev-CppTRIAL.PASS.!!!.cpp `X' undeclared (first use this function)
I have to write a loop assigning a variable x to all positions of a string variable and I'm stuck. I don't have extensive experience with arrays and I'm also a bit confused about C-String. The problem is below.
"Given the following declaration and initialization of the string variable, write a loop to assign 'X' to all positions of this string variable, keeping the length the same.
char our_string[15] = "Hi there!";
(Please note this is a 'C-string', not C++ standard string.)"
I'm trying to create a simple calc program that does all the elementary calculations. How to get it to add and multiply continuously without crashing. but now i need to figure out how to ask the user if they want to continue or not. I'm having trouble here because in the while statement i have a scanf which asks for the operator symbol. and then asks for number in the second scanf..
So basically a user would have to enter 'R' twice for the message to pop up! Also i'm not sure how i would quite the program if they put in a 'N' for no. would return 0; work? What if they press 'Y' for yes, what would the return have to be then?
Here's a snippet of the code
int main () {
double result;
double new_number;
char symbol;
result = 0;
while(1==scanf(" %c", &symbol) && symbol == 'R' && symbol =='r')
[Code] .....
I have two files like original.txt and replace.txt which has equal nbr of lines in both of them.
I need to loop through these two files line by line and replace the line in original.txt to the line in replace.txt
eg :
output.txt :
1|raj|65.4|Y|
1|ramesh|65.4|Y|
replace.txt :
1|raj|65.4|Y|
Cannot be processed|1|ramesh|65.4|Y|
What I need here is when reading of output.txt reaches second line of file "1|ramesh|65.4|Y|", it has to be replaced with the second line in replace.txt "Cannot be processed|1|ramesh|65.4|Y|".
1|ramesh|65.4|Y| --> Cannot be processed|1|ramesh|65.4|Y|
After the end of loop the contents of two files should be like :
original.txt :
1|raj|65.4|Y|
Cannot be processed|1|ramesh|65.4|Y|
replace.txt :
1|raj|65.4|Y|
Cannot be processed|1|ramesh|65.4|Y|
The files can have variable number of lines but both will have same number of lines each.
I need to do make a loop inside a condition. Can it be done? I don't want to call another function to do it. Any way at all without calling separate function inside the if? I just want to do:
if (
for (int i = 0; i<=10; i++)
{
//stuff related to the for loop
} )
{
//stuff related to the initial if condition
};
Code:
......
static char str[BIG_STRING];
static char str_copy[BIG_STRING];
char **words;
int max_words = 10;
[Code] ....
I'm confused with this last [for] loop; How is ptr++ applied for non-integer value? Ptr is clearly a char, it comes from str, which reads string line from file.
I come from C# background, I have never met for...loop which irritates by using [somechar]++, not [someinteger]++;
What is actually going on there?
Some other similar example might be:
Code:
(iColor+(_parts[j]%length)*3),
where iColor is static unsigned char iColor[] array;
I would expect to see iColor[somevalue] + (_parts[j]%length)*3), but here in C++ I sometimes see that integer is being added directly to the array. What does it mean, what happens?
This is with Linux gcc
Code:
typedef struct _a
{
int id;
} a;
typedef struct _b
{
a my_a;
my_a.id = 1; // error: expected specifier-qualifier-list before "my_a"
} b;
I get error: expected specifier-qualifier-list before "my_a"
I must set the id for the kind of struct created inside the struct def because main() will be casting based on this id. Thats how I will know which structure b contains by it's id, there could be hundards of different structs with different values I will cast to the correct one and know it's members by it's id. How do I ?
In the following code:
#include <iostream> // For stream I/O
using namespace std;
int function(int a) {
return a;
}
int main() {
function(int b);
}
Why is creating a variable inside the function argument list not allowed. Any reason other then for the language syntax or just for the language syntax?
Say you had:
class Foo{
public:
//...
void funky();
[Code] .....
Would each instance of Foo create a new counter variable, or would it remain the same for all of them, i.e. baz.funky() would always use the same counter variable? What if the class was a template?
I've been working on a program on and off for around a week now and I've been struggling towards the end of the program.First of all, the program is a maths quiz which generates two random numbers per question.I'll give you one part of my code:
Code:
srand ( time(NULL) ); //seeds the random number generator
int score = 0;
int a = rand()%12 +1; //generates a random num between 1-12
int b = rand()%12 +1;
int c = a+b;
int d;
}
[code]....
I've basically copied the above code 10 times and changed the variables by going through the alphabet e.g.
Code:
int a = rand()%12 +1; //generates a random num between 1-12
int b = rand()%12 +1;
int c = a+b;
int d; all the way to
Code:
int an = rand()%12 +1;
int ao = rand()%12 +1;
int ap = rand()%12 +1;
int aq = an+ao-ap;
int ar;
Now what I'm going to do is remove all the declared variables and create a loop. But my problem is; If I wanted to declare four variables for e.g.
Code:
int a = rand()%12 +1;
int b = rand()%12 +1;
int c = rand()%12 +1;
int d = a+b-c;
Would I place the srand( time(NULL)); inside the loop? it's confusing because I know an example of a basic loop with an array would be:
Code:
#include <stdio.h>
#include <conio.h>
int main(void)
{
int test[5]={21,18,47,21,4};
int I;
int total=0;
for (I=0;i<5;i++)
total += test[I];
}
[code]....
how or where to include the random number generator in the loop and to make it ask 10 questions at random.