Member Avatar for soche123

I don't get what this error mean in line 17 or 18..

#include <iostream>
#include <conio.h>
using namespace std;

int main()
{
    int players;
     int years=3;
    cout<<"Enter no. of players";
    cin>>players;

    int record[players][years];
    for(int i=0; i<=players; i++)
    {
        for(int j=0; j<=years; j++)
        cout<<"Enter runs scored by player"<<":"<<i+1<<": ";
        cin>>record[i][j];


    }
    cout<<"\n\tYear1\tYear2\Year3";
    cout<<"\n\tRuns\tRuns\Runs";
    cout<<"\n*************************************"<<endl;
    for(int i=0; i<=players; i++)
    {
        cout<<"\nPlayer"<<i+1<<"\t"<<endl;
        for(int j=0; j<=years; j++)
        cout<<record[i][j]<<"\t";
        cout<<endl;
    }

    getch();
    return 0;
}
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  • 2 Replies
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  • Latest Post Latest Post by rubberman

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Generated

@/soche123: @/mike_2000_17 correctly points to the scoping root of that GCC message (the loop-local j isn't visible where it's used). Additional issues worth fixing so the program is both correct and portable:

  • Loop bounds: iterate with < (0..n-1), not <=, to avoid out-of-range indexing.
  • Storage: int record[players][years] relies on a compiler extension (variable-length arrays). Prefer std::vector for dynamic sizes.
  • Strings and escapes: sequences like \Year3 are malformed; use \t for tabs or write literals without stray backslashes.
  • Portability: conio.h/getch() are nonstandard; use standard input/output and std::cin.get() if a pause is needed.
  • Input validation: verify players and years are positive before allocating.

A compact, modern pattern is a 2D vector with strict bounds and input checks:

#include <iostream>
#include <vector>

int main() {
    int players = 3, years = 3;
    std::vector<std::vector<int>> record(players, std::vector<int>(years));

    for (int i = 0; i < players; ++i)
        for (int j = 0; j < years; ++j) {
            std::cout << "Player " << (i+1) << ", Year " << (j+1) << ": ";
            if (!(std::cin >> record[i][j])) return 0;
        }

    // print or process record safely...
}

As @/rubberman advised, always use braces for loops and conditionals to prevent scope and maintenance errors when adding lines later. Validate inputs and prefer standard containers for safer, clearer code.

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Member Avatar for mike_2000_17

You are missing the curly braces in this for loop:

    for(int j=0; j<=years; j++)
    cout<<"Enter runs scored by player"<<":"<<i+1<<": ";
    cin>>record[i][j];

You'll see it better if you space it out and indent properly:

    for(int j = 0; j <= years; j++)
        cout << "Enter runs scored by player" << ":" << i+1 << ": ";

    cin >> record[i][j];

As you see, the cin >> record[i][j]; is outside the scope of the for-loop. The error message is telling you that the variable j is undefined at that point. The reason the error message is weird is because it use to be (before the ISO standard) that the variable declared in the for-loop would exist in the scope enclosing the for-loop (e.g., holding the value it had at the last iteration), this rule has changed and is no longer allowed.

To fix the error, you need this:

    for(int j = 0; j <= years; j++) {
        cout << "Enter runs scored by player" << ":" << i+1 << ": ";
        cin >> record[i][j];
    };
Member Avatar for rubberman

Mike2K points out a common coding issue - proper scoping of loops. My personal process says "scope everything" - loops, conditionals (if/then/else), etc. IE, place proper brackets around all loops and conditional blocks of code. Then, when you need to add a line to them, they will still be properly constrained! :-)

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