Incompatible types problem in C / Variable Problem

[pandaemonium]

I have two quick problems with the code I am writing:

First, I define a struct of char arrays (strings) and then try accessing the same. I get an "incompatible types in assignment" error:

struct {
     char name[50];
     char value[50];
} varlist[20];
 
int main(int argc, char *argv[]) {
     varlist[0].name = "foo";
     varlist[0].value = "bar";
}

.

The second question I think has to do with a pointer issue, but I'm not sure.

char *mymethod(char str[]){
     char *result = malloc(100*sizeof(char));
     strcpy(result, atoi(global_variable));
     // global_variable is defined in a header file
     return result;
}

.
When I run it, I get a "Passing arg 1 of 'atoi' makes pointer from interger without a cast" and I get the same error for arg 2 of strcpy.

Please help, and thanks in advance.

[jorba101]

I have two quick problems with the code I am writing:

First, I define a struct of char arrays (strings) and then try accessing the same. I get an "incompatible types in assignment" error:

struct {
     char name[50];
     char value[50];
} varlist[20];
 
int main(int argc, char *argv[]) {
     varlist[0].name = "foo";
     varlist[0].value = "bar";
}

.

It will not work. You're assigning the field "name" to point to a literal (namely "foo"). What you want to do is fill in the memory already pointed by name (as you have done when defining the var). You have to do strcpy. Something like...

strcpy( varlist[0].name, "foo");

This will copy the string "foo" inside the memory pointed by varlist[0].name.

The second question I think has to do with a pointer issue, but I'm not sure.

char *mymethod(char str[]){
     char *result = malloc(100*sizeof(char));
     strcpy(result, atoi(global_variable));
     // global_variable is defined in a header file
     return result;
}

.
When I run it, I get a "Passing arg 1 of 'atoi' makes pointer from interger without a cast" and I get the same error for arg 2 of strcpy.

Please help, and thanks in advance.

I think you need function itoa (integer to ascii) instead of atoi (ascii to integer). It does not make sense to give an integer as a parameter to strcpy (this function is expecting a pointer to char -i.e. a string- in arg2).

[pandaemonium]

Thank you... but what is the ISO standard way to convert ints to ASCII? According to man itoa it doesn't fall under standard C.

[jorba101]

Woops, I did not know it was not standard.

Then you can try:

sprintf( yourTargetString, "%d", yourIntVar );

[Laharl]

Yeah, sprintf is about the only standard way to do int->ascii string. I've never understood why itoa isn't standard.