How I solve this simple problem with CodeBlock?

Question

I'm a beginner and have 3 file to sum recursive an array.

array.h

int sum(int n, int a[]);
void create_array(int n, int a[]);

array.c

#include<stdio.h>
#include<stdlib.h>
#include "array.h"
void create_array(int n, int a[]){
    int i;
    for( i=0;i<n;i++){
        printf("Inserire il %d elemento dell'array\n",i);
        scanf("%d",&a[i]);
    }
    return;
}

int sum(int n, int a[]){
    if(n>0){
        return a[n-1]+sum(n-1,a);
    }
    return 0;
}

main.c

#include <stdio.h>
#include <stdlib.h>
#include "array.h"

int main()
{
    printf("Inserire la dimensione dell'array\n");
    int n;
    scanf("%d",&n);
    int a[n];
    create_array(n,a);
    int res=sum(n,a);
    printf("La somma degli elementi e' %d\n", res);
    return 0;
}

PROBLEMS

||=== Build file: "no target" in "no project" (compiler: unknown) ===|
undefined reference to `create_array'|
undefined reference to `sum'|
||error: ld returned 1 exit status|

I have put these 2 files in the same directory. If I compile and run them with terminal cmd Windows they started. But if I try to compile from IDE CodeBlocks says this errors. Anyone help?

Answer 1

There's a problem with the way you've told Code::Blocks that these files are all related.

What I did:

■ opened up the IDE and clicked NewFile->Empty File

■ copied the first block of code, pasted it and saved as array.h

■ copied the second block of code, pasted it and saved as array.c

■ copied the third block of code, pasted it and saved as main.c

■ Hit "Build and Run"

Then got exactly the same set of errors that you did.

What you needed to do instead, was hit New File->Project, select Console Application, select C, enter a project name (the exe will have the same name by default, though you can change this) From there, you'll get a folder created that contains a.CBP file and a main.c file. You can then hit "New File" and this time, it will ask you if you want to add it to the current project.