Стеки на Си

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
typedef struct info_t
{
    unsigned phone;
    char surname[32];
}   TInfo;
 
typedef struct node_t
{
    TInfo info;
    struct node_t* next;
}   TNode;
 
//-----------------------------------------------------------------------------
TNode* Push(TNode** stack, const TInfo* info)
{
    TNode* node = malloc(sizeof(TNode));
    node->info = *info;
    node->next = *stack;
 
    *stack = node;
 
    return *stack;
}
//-----------------------------------------------------------------------------
TInfo Pop(TNode** stack)
{
    TNode* node = *stack;
    TInfo info = node->info;
 
    *stack = node->next;
 
    free(node);
 
    return info;
}
//-----------------------------------------------------------------------------
void Clear(TNode** stack)
{
    while (*stack)
    {
        Pop(stack);
    }
}
//-----------------------------------------------------------------------------
void Print(const TNode* stack)
{
    for (; stack; stack = stack->next)
    {
        printf("%d\t%s\n", stack->info.phone, stack->info.surname);
    }
}
//-----------------------------------------------------------------------------
TNode* GetInfo(FILE* f)
{
    TNode* stack = NULL;
    TInfo info = {0, {0}};
    size_t length;
    size_t maxlen = 0;
 
    while (fscanf(f, "%u %31s", &info.phone, info.surname) == 2)
    {
        length = strlen(info.surname);
 
        if (maxlen < length)
        {
            Clear(&stack);
            maxlen = length;
        }
 
        if (maxlen == length)
        {
            Push(&stack, &info);
        }
    }
 
    return stack;
}
//-----------------------------------------------------------------------------
 
int main(int argc, const char* argv[])
{
    if (argc != 2)
    {
        fprintf(stderr, "Usage: program <FILE>\n");
        return EXIT_FAILURE;
    }
 
    FILE* f = fopen(argv[1], "r");
 
    if (f == NULL)
    {
        perror(argv[1]);
        return EXIT_FAILURE;
    }
 
    TNode* stack = GetInfo(f);
 
    fclose(f);
 
    Print(stack);
 
    Clear(&stack);
 
    return EXIT_SUCCESS;
}

if (argc != 2)
    {
        fprintf(stderr, "Usage: program <FILE>\n");
        return EXIT_FAILURE;
    }

int main(void)
{
  
 
    FILE* f = fopen("aa.txt", "r");
 
    if (f == NULL)
    {
        perror("aa.txt");
        return EXIT_FAILURE;
    }
 
    TNode* stack = GetInfo(f);
 
    fclose(f);
 
    Print(stack);
 
    Clear(&stack);
 
    return EXIT_SUCCESS;
}