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int main(int argc, char *argv[]) {
cout << "Ist yoo acited? \n"
char j
cin >> input;
cout << input;
system("PAUSE");
return 0;}
It says in the error message that 'j' is undeclared.
I'm obviously new, and just trying out stuff out.
You're missing a semicolon at the end of j's declaration, and your cout command. You may also wish to provide j with a default value. Also, you don't seem to have declared the variable input.
You're missing a couple semi-colons( ; ) and you also didn't declare input:
int main(int argc, char *argv[]) {
cout << "Ist yoo acited? \n";
char j, input;
cin >> input;
cout << input;
system("PAUSE");
return 0;
}
Related
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Closed 2 years ago.
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I have simplified the code to get rid of unrelated objects. This is my code:
#include <iostream>
#include <fstream>
using namespace std;
fstream asdf;
int input;
void import_image(){
asdf.seekg(0);
char character;
for(int k = 0; k < 40; k++){
asdf.get(character);
input = (unsigned int)(unsigned char)character;
}
}
void print_hello_world(){
for(int rows; rows <= 27; rows++){
cout << "hello world" << endl;
}
cout << "goodbye.";
}
int main(){
asdf.open("abc.txt", ios::binary | ios::in);
cout << asdf.is_open() << endl;
import_image();
//cout << endl;
print_hello_world();
return 0;
}
Running this code results only in
1
goodbye.
--------------------------------
Process exited after 0.1511 seconds with return value 0
however removing double slash (simply adding cout << endl;) fixes everything. I have no idea why it happens and would like to now why is it so. I know that variable "rows" has no value, but why does printing a new line fix everything?
The new "endl"
is a great sign
that what you see,
is called "UB".
Your program has Undefined Behavior (UB) because your int rows that you use for the loop iterations is uninitialized.
By UB definition anything may happen. Activate all (sane) compiler warnings to find errors like this earlier in your development process.
Undefined behavior yield working programs by completely random changes (for example the addition of std::endl) but in the end it's undefined behavior.
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My while loop is not working. The code runs correctly on the Codecademy website compiler. I then compile it with Visual Studio, run it from the Command prompt and input a number. The program stops prematurely even if the number is the correct one.
#include <cstdlib>
#include <iostream>
int main() {
int answer = 8;
int guess;
int tries;
std::cout << "I have a number between 1-10.\n";
std::cout << "Please guess it: ";
std::cin >> guess;
while (guess != 8 && tries < 50) {
std::cout << "Wrong guess, try again: ";
std::cin >> guess;
tries++;
}
if (guess == 8) {
std::cout << "You got it!\n";
}
}
As #rsjaffe and #Ken White have said in the comments, the tries variable is unitiailized, meaning that the location in memory that the variable is pointing to is "junk" (left over memory). Try to give it an initial value, like this:
int tries = 0;
which will instantiate and initialize the tries variable.
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I made a function that will reverse the string, but the output of the reversed string always shifts towards the right by one character.
#include <iostream>
#include <string>
using namespace std;
void reverse(string string1)
{
cout << endl;
for (int i = string1.size(); i >= 0; i--)
{
cout << string1[i];
}
cout << endl;
}
int main()
{
string string1;
getline(cin, string1);
reverse(string1);
system("pause");
return 0;
}
Your first output is of a character that does not exist.
std::string's leaky abstraction means that your first iteration is printing '\0', which apparently looks like a space in your configuration.
Begin at string1.size() - 1.
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What have I done wrong with the following code?
#include <iostream>
using namespace std;
main ()
{
int a;
int b;
int sum;
cout << "Enter first number \n";
cin >> a;
cout << "Enter second number \n";
cin >> b;
sum = a+b;
cout << "The sum of both numbers is" << sum << endl;
return 0;
}
Does the editor you are using tells errors, so the code is not executing? Or som exception rises? Or it is executing but nothing is shown? Please specify your problem accurately.
Anyway, you must use
int main ()
instead of
main()
Notice that your code returns a value. The last line of you code is:
return 0;
Thus, you must specify an int return type.
Check your initial lines with this.
#include <iostream>
using namespace std;
int main ()
{
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I am trying to get only the alphabetic characters from an array of characters entered by the user. Here is a snippet:
const int SIZE(100);
int main()
{
char* entryTextArray = new char[SIZE];
char* adjustedTextArray= new char[SIZE];
int i, j;
cout << "Enter text, and I will tell you if it is a palindrome!" << endl;
cin.get(entryTextArray, SIZE);
cout << "Length of char array is " << strlen(entryTextArray) << endl;
for(i=0, j=0; i <= (strlen(entryTextArray)); i++) {
if(isalpha(entryTextArray[i]) && (entryTextArray[i] != '\0')) {
adjustedTextArray[j] = entryTextArray[i];
cout << adjustedTextArray[j] << endl;
j++;
}
}
cout << adjustedTextArray << endl;
}
When I compile, the cout of the adjustedTextArray displays the proper individual entrys, but the cout outside of the loop is the entry text, followed by garbage. I have no idea what is wrong! Help?!
You have the condition:
if (something && (entryTextArray[i] != '\0'))
so you are explicitly avoiding to copy the NUL terminating value from entryTextArray to adjustedTextArray. So you need to place it manually.
But since you are working in C++ using std::string just makes more sense.