In C++ I can allocate an array of strings (say 10 strings) very easily as:
string* arrayOfString = new string[10];
however I don't know how to do it in ANSI C. I tried:
char** arrayOfString = (*(char[1000])) malloc (sizeof (*(char[1000])));
But the compiler (MinGW 3.4.5) keeps saying that it is "Syntax error". How to do it right? Thanks.
If each string is of same size which is known at compile time, say it is 100, then you can do this1:
typedef char cstring[100]; //cstring is a new type which is
//a char array of size 100
cstring *arrstring = malloc (1000 * sizeof (cstring));
int i;
for( i = 0 ; i < 1000 ; ++i)
strcpy(arrstring[i], "some string of size less than or equal to 100");
for( i = 0 ; i < 1000 ; ++i)
printf("%s\n", arrstring[i]);
Demo : http://ideone.com/oNA30
1. Note that as @Eregrith pointed out in the comment that cast is not advised if you compile your code as C. However, if you compile it as C++, then you need to write (cstring*)malloc (1000 * sizeof (cstring)) but then in C++, you should avoid writing such code in the first place. A better alternative in C++ is, std::vector<std::string> as explained at the bottom of this post.
If the size of each string is not known at compile time, or each string is not of same size, then you can do this:
char **arrstring = malloc(sizeof(char*) * 1000); //1000 strings!
int i;
for(i = 0 ; i < 1000; ++i)
arrstring[i] = (char*) malloc(sizeof(char) * sizeOfString);
I'm assuming same size sizeOfString for all 1000 strings. If they're different size, then you've to pass different value in each iteration, something like this:
for(i = 0 ; i < 1000; ++i)
arrstring[i] = malloc(sizeof(char) * sizeOfEachString[i]);
I hope that helps you, and I also hope you can do the rest yourself.
By the way, in C++, you should not do this:
string* arrayOfString = new string[10]; //avoid new as much as possible!
Instead, you should do this:
std::vector<std::string> strings;
strings.reserve(10);
Try this one to allocate 100 strings. Each string is at most 1000 characters long.
char** arrayOfString = (char**) malloc (sizeof(char[100][1000]));
#define N 10 // Number of strings
#define M 20 // Size of the strings
/* Please check malloc return value is not NULL */
char **arrayOfString = malloc(sizeof *arrayOfString * N);
for (i = 0; i < N; i++) {
arrayOfString[i] = malloc(M);
}
i < N in the for?
-xc option to gcc to compile it as a C program or rename the filename extension to .c.void as a function parameter? Why include stdio.h? Why { now in a new line? Why ** not bound to the function identifier?