Is this memory leak from my program or the computer? How can I fix it?

Question

I was practising my programming and memory allocation.When i execute without valgrind the program works and it does what it needs to do. Then i executed with valgrind to see if i had any memory leaks.This is what i got when executing with valgrind. Im kind of new and i cant find why do i have so many memory leaks or errors. The code is below. Thanks!!

 1 #include <stdio.h>
  2 #include <stdlib.h>
  3 int* fun(int *l){
  4          int *k;
  5          k = (int *)malloc (4*sizeof(int));
  6          for(int i = 0; i<4; i++){
  7              k[i] = 2*l[i];
  8              l[i] += 1;
  9          }
 10          return k;
 11          free(k);
 11 }
 12 int main(){
 13          int *s;
 14          int *t;
 15          s = (int *)malloc (4*sizeof(int));
 16          s[0] = 2; s[1] = -3; s[2] = 5; s[3] = 0;
 17          t = fun(s);
 18          for(int i = 0; i<4; i++){
 19              printf(" %d   %d\n", s[i], t[i]);
 20          }
 21          free(s);
 22          free(t);
 23          return 0;
 24 }

Answer 1

The free statement in your function fun is never executed because of the return statement just before it.

Also, you might consider to use vector<int> instead of *k , *l , *s and *t .

Example:

#include <vector>
using namespace std;

vector<int> s;      
s[0]=1;