Thread: How to create a C function

How do I create a C function? Something so that I can define a certain word, say help, as a function that is equivalent to:
printf("[Help stuff here]");

Oh my...

I don't understand what you want, can you try explaining it a different way?

You see, my problem is that I have a long bunch of code that appears repeatedly in my program. I don't want to type it over and over, and copying and pasting is too much work. So how can I make it so that I type one word instead of a whole bunch. E.g. the follwing 2 pieces of code are equivalent:

1. calculate

2. int x;
printf("blahblahblah");
int y;
printf("blahblahblah");
scanf("%d",x);
printf("blahblahblah");
scanf("%d",y);
int z;
z=x+y;
printf("blahblahblah);

So how can I do that?

You can create a function before the main function, eg

Code:

int calculate()
{
   int a, b;
   /* prompt a*/
   scanf("%d", &a);
   /* prompt b */
   scanf("%d", &b);

   return a+b;
}

main()
{
   int sum;
    ...
    sum = calculate();
    ...
    return 0;
}

or you can define it at the end of main (conventional way) in which case you need to have a PROTOTYPE before main eg,

Code:

int calculate();   /* <-- prototype */

main()
{
   int sum;
    ...
    sum = calculate();
    ...
    return 0;
}

int calculate()
{
   int a, b;
   /* prompt a*/
   scanf("%d", &a);
   /* prompt b */
   scanf("%d", &b);

   return a+b;
}

Hope this helps.

Building upon what Quzah just said:

Code:

#include <ctype.h>

int main( void )
{
    int myfunc( char *s) {
        for(;*s;s++)
             *s = toupper(*s);
    }
    char s[] = "hello";

    myfunc(s);
    puts(s);

    return ~-1; /* Just for fun. */
}