无法在特定条件C90下调用功能

Question

The code

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/*Version 1*/
void replace_word(char *word);
void add_new_word_dictionary(void);
void do_nothing(void);
void return_basic(void);
void check_word(void);
void compute_words(void);
void compute_characters(void);
void compute_ch_sp(void);
void compute_num_dif_words(void);
void create_istogram(void);
void save_file(void);
int get_choice(void);
char * add_text(void);

int main()
{
   int choice = 0;
   char string[40] = {"test"};
   while((choice = get_choice() != 5))
   {
       printf("your choice is %d",get_choice());
       if(choice == 0)
       {
           printf("test_succesful");
           printf("The choice is %d",choice)
       }
       printf("The choice is %d",choice);
    }
    return 0;
}

void replace_word(char *word)
{
    printf("\n replace_word\n");
    return;
}

void add_new_word_dictionary(void)
{
    char word[50] = {"s"};
    printf("\nPlease enter the word\n");
    scanf("\n%s",word);
    printf("Your word is %s",word);
    return;
}

void do_nothing(void)
{
    printf("do_nothing");
    return;
}


void return_basic(void)
{
    printf("\n return basic \n");
    return;
}

void check_word(void)
{
    printf("\ncheck word\n");
    return;
}

void compute_words(void)
{
    printf("\n compute_words \n");
    return;
}

void compute_characters(void)
{
   printf("\n compute characters \n");
   return;
}

void compute_ch_sp(void)
{
printf("\n compute_ch_sp \n");
return;
}

void compute_num_dif_words(void)
{
    printf("\n compute_num_same_words \n");
    return;
}


void create_istogram(void)
{
    printf("\n create istogram \n");
    return;
}

void save_file(void)
{
    printf("\n save_file \n");
    return;
}


int get_choice(void)
{
    int choice = 0;
    printf("\n Select a choice from  the below \n");
    printf("\n Select 0 to add text \n");
    printf("\n Select 1 to add new words in the dictionary \n");
    printf("\n Select 2 to enter  enter correction mode \n");
    printf("\n Select 3 to save the text \n");
    printf("\n Select 4 to see the statistics about your text \n");
    printf("\n Select 5 to exit the program\n");
    scanf("\n%d",&choice);
    return choice;

}


char  *add_text(void)
{
    char word[40];
    printf("\n Add the word \n");
    scanf("\n%s",word);
    return word;
}

The problem: When choice is 0 I want the add_text function to be called..But that is not happening..I threw a bunch of printf< /em>内部 main（）以查看发生了什么并得出结论， opeach 它总是（几乎）的值，因此 add_text 函数不被调用...我该如何解决？

是的，您可以看到我是一个初学者...