Question

In C programming, how do i check whether char array[] contains int, float or double value and also store the value using respective data type?

Example:
If the char array[] contains 100 – its int value and should be store in int a.
if the char array contains 10000.01 its float value and should be stored in float b.

Answer 1

The only way you can store mixed types in an array is to have an array of pointers.

You’d need to use a struct or a union to store each one too like so:

#define TYPE_INT 1
#define TYPE_FLOAT 2
#define TYPE_STRING 3

typedef struct  {
  int type;
  void *ptr;
} object;

object* mkobject( int type, void * data ){
  object * obj = (object*)malloc(COUNT*sizeof(object))
  obj->type = type;
  obj->ptr = data;
  return obj;
}

No using the above you can store type information

void * intdup( int original ) {
  int * copy = (int*) malloc(1*sizeof(int));
  *copy = original; 
  return (void*) copy;
}

void * floatdup( float original ) {
  float * copy = (float*) malloc(1*sizeof(float));
  *copy = original; 
  return (void*) copy;
}

int COUNT = 3;
objects** objectlist = (object**)malloc(COUNT*sizeof(object*))

// -- add things to the list
int a_number = 2243;
float a_float = 1.24;
char* a_string = "hello world"; 


objectlist[0] = mkobject( TYPE_STRING, strdup(a_string) );
objectlist[1] = mkobject( TYPE_INT, intdup(a_number) );
objectlist[2] = mkobject( TYPE_FLOAT, intdup(a_float) );


// iterate through a list

for ( int x = 0; x < COUNT; x++ ){

   switch( objectlist[x]->type ){

      case TYPE_STRING:
       printf("string [%s]\n",(char*) objectlist[x]->ptr );
       break;
      case TYPE_FLOAT:
       printf("float  [%f]\n", *(float*) objectlist[x]->ptr );
       break;
      case TYPE_INT:
       printf("int    [%d]\n", *(int*) objectlist[x]->ptr );
       break;
      default;
       printf("unintialized object\n");
       break;

   }

}