I have problem with assigning value to string array in c. The code is part of a hangman game

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>

int main()
{
    srand(time(0));
    int random = rand() % 5;

    char *sWords[] = {"banana", "apple", "GOAT", "jordan", "zhiki"};
    printf("%s\n", sWords[random]);

    char *sTempWord = sWords[random];

    char *sTempArr;
    for (int i = 0; sTempWord[i] != '\0'; i  )
        sTempArr[i] = '_';

    for (int i = 0; strlen(sTempArr); i  )
        printf("%c ", sTempArr[i]);
}

There are no errors, and when I run the program it just exits. The plan is to get random word from the list, create temporary array with the length of the randomly-selected word and assing all elements with value '_'.

Also, when I try to make array with constant value, (like char sTempArr[len] where len=strlen(sTempWord), it says: expression must have a constant value

CodePudding user response：

When declaring an array, the compiler needs to know the length at compile time (e.g. the value can't be a variable).

You can either create an initial empty array with a known number of items (you will need to make sure it's big enough to fit any word from sWords, including null terminator):

char sTempArr[100];

or you can allocate dynamic memory at runtime with something like malloc():

#include <stdlib.h>

int len = strlen(sTempWord)   1;   //  1 for '\0'
char *sTempArr; = malloc(len);

// ...

free(sTempArr);    // When you are done using the array

They are not the same.

CodePudding user response：

1. Not initialized pointer.

    char *sTempArr; 

2. You do not null character terminate the string

    for (int i = 0; sTempWord[i] != '\0'; i  )
        sTempArr[i] = '_';

3. As the string is null character terminated you can't call strlen

    for (int i = 0; strlen(sTempArr); i  )
        printf("%c ", sTempArr[i]);

    char sTempArr[strlen(sTempWord)   1];
    int i;
    for (i = 0; sTempWord[i] != '\0'; i  )
        sTempArr[i] = '_';
    sTempArr[i] = 0;

    for (i = 0; strlen(sTempArr); i  )
        printf("%c ", sTempArr[i]);