Few questions about C syntax

Question

I have a few questions about C syntax.

1. ch = (char *) malloc( sizeof( char ) * strlen(src) ); What do the first brackets mean (char *) ?

Answer 1

In simple terms:

1) since malloc returns a pointer of type void, you are casting that pointer to a pointer of type char so that the variable ch will later hold an array of characters (a string )

2) the single quotation marks are mainly used because a switch statement in C always expects an INTEGER and, not a string. having a character surrounded by single quotations would return the integer representation of the character.

3) This is a common problem when using scanf, basically it is caused by by the carriage return that is entered from the previous scanf. I would recommend that you always flush the input before using it.

Here's an example:

#include 

int main (void)
{
    char line[200];
    while(1)
    {
        printf("\nenter a string: ");
        fflush(stdout);         // safety flush since no newline in printf above
        scanf(" %[^\n]",line);  // note space character
        printf("you entered >%s<\n",line);
    }
    return 0;
}