Question 38518 in Ubuntu Question posted in
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Why can't I assign 2 to all the elements in an array in C/C++ by this way? – Ubuntu

My system is Ubuntu

Here is my code:

#include <stdio.h>
#include <stdlib.h>
#include <iostream>

#define LEN 16

using namespace std;

int main(){
    int a[16] = {2};
    for (int i=0; i<16; i++)
    {
        cout << a[i] << ' ';
    }
}

I compiled it by this command in terminal : g++ t1.cpp -o t1 && ./t1

but the result is

2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Tags:

2

Answers


  1. 0

    Any decent book, tutorial or class should have taught you that the definition

    int a[16] = {2};

    is equivalent to

    int a[16] = {2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};

    If you want to initialize all elements to a single value you need to explicitly do it.

    You can also use std::fill after definition to set every element to a value:

    int a[16];
std::fill(begin(a), end(a), 2);

    And some nitpicking: What you’re doing is initialization, not assignment.

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  2. 0

    You’ve assigned a 2 to index 0 of your array.

    You may wish to use std::fill.

    const int size = 16;

int main() {
    int a[size];

    std::fill(a, a + size, 2);

    return 0;
}
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