将 10 个整数存储到数组 C++ 中的问题

Question

Ok, I'm very confused as to why this happens. All I'm trying to do is put 10 integers from input into an array. Why is this happening.

#include <iostream>
using namespace std;

int getData(float intArray[10]);

void printData(float intArray[10]);



int main() {
float myArray[10];
getData(myArray);
printData(myArray);

cin.get();
cin.ignore();


}

int getData(float intArray[]) {
    for (int i = 0; i < 10; i++)                                  
    {                                                        
        std::cout << "Enter a number:";
        std::cin >> intArray[10];
    }
    return 1;
}

void printData(float intArray[10]){

    cout << intArray;

    }

If you could please tell me where I'm going wrong, that would be very much appreciated. Thank you!

Answer 1

From how your code is written, you're only adding the user's input to the [10] element of intArray[] within that for loop you created. Additionally, any information added to the array at intArray[10] or beyond is placed out of bounds.

The only way I can really demonstrate what I mean is...

for (int i = 0; i < 10; i++)
{
    std::cout<<"Enter a number:";
    std::cin >> intArray[i];
}

Another thing I noticed is you're creating another array with the same name in your printData method. You should instead pass the intArray you're filling up with information to this method and use it to display your information.

Answer 2

The problem lies in this block of code-

for (int i = 0; i < 10; i++)                                  
    {                                                        
        std::cout << "Enter a number:";
        std::cin >> intArray[10];
    }

As mentioned in other answers and comments you are storing all the values in the 10th memory slot of the array.

As per your comment

I forgot to mention, the output is just random integers and characters. EX: 00B3F724

00B3F724 => These are the memory address allocated to the array and which will hold the elements which will be inserted.

How array actually works-

float myArray[10];

The above snip creates 10 units of memory space. The units differ on the type which the array will hold. In this case it is holding float values, so each memory space will be of 4 bytes. All of these spaces have an address for lookup and other operations. All these spaces are expecting a float value to be inserted.

As you are using the loop you have to loop through the array(all the memory slots allocated to the array) and allocate a float element to each one of them and not only the last element(10th). Effectively your for loop will become

 for (int i = 0; i < 10; i++)                                  
        {                                                        
            std::cout << "Enter a number:";
            std::cin >> intArray[i];
        }

Instead of intArray[10] insert values like this intArray[i] . As i will traverse through all the slots on every iteration of the loop insert a values to a slot.

Your code will look like

#include <iostream>
using namespace std;

int getData(float intArray[10]);
void printData(float intArray[10]);
int main() {
float myArray[10];
getData(myArray);
printData(myArray);
cin.get();
cin.ignore();


}

int getData(float intArray[]) {
    for (int i = 0; i < 10; i++)                                  
    {                                                        
        std::cout << "Enter a number:";
        std::cin >> intArray[i];
    }
    return 1;
}

void printData(float intArray[10]){

    cout << intArray;
    }

Answer 3

As you know if an array is declared as myArray[10], its index ranges from 0-9. Putting a value in myArray[10] will go out of bound and will produce garbage value.

In getData(float intArray[]) you are always overwriting the content of intArray[10] while it is out of bound so it is not being stored in an actual array. You should write your getData(float intArray[]) as following :

int getData(float intArray[]) {
for (int i = 0; i < 10; i++)                                  
{                                                        
    std::cin >> intArray[i];
}
return 1;
}

Also in printData(float intArray[10]) you are only printing the base address of the array (ie the name of the array gives the address of the 0th index).So the correct code would be:

 void printData(float intArray[])
{
  for(int i=0;i<10;i++)
 {
  cout << intArray[i]<<" ";
 }
}

Answer 4

Simply change,

std::cin >> intArray[10];

to,

std::cin >> intArray[i];

What you are doing wrong:

you are storing the value at the 10th position (actually it is 11th position) again and again and the value at 10th position replaces with the new value again and also the 10th position doesn't exist in the array because the index of the array starts from 0, so your array has the index values from 0 to 9.