Learn point C language (32): function

A function in C can return any type other than an array (excluding array pointers).

Does not specify the return type, in the previous C language version is the default return int, now C99, C + + is not supported.

void means that no return value is required; If the other statement must have a return statement.

In the main function (just the main function) if you forget return, some compilers will automatically add return 0;

1. Each execution return statement function will exit:

#include　<stdio.h>

int　main(void)
{
　　printf("111\n");
　　printf("222\n");

　　return　0;　/*　之后的语句将不会执行　*/

　　printf("333\n");
　　printf("444\n");

　　getchar();
　　return　0;
}

2. If the function does not return a value, you can borrow the returned without parameters:

#include　<stdio.h>

void　prn(void);

int　main(void)
{
　　prn();
　　getchar();
　　return　0;
}

void　prn(void)　{
　　printf("111\n");
　　printf("222\n");

　　return;　/*　无参数的　return　*/

　　printf("333\n");
　　printf("444\n");
}

3. Return is not followed by an "equal sign", but the returned value can also be written in parentheses:

#include　<stdio.h>

long　long　MySqr(int　x);

int　main(void)
{
　　int　i　=　9;

　　i　=　MySqr(i);
　　printf("%d\n",　i);

　　getchar();
　　return　0;
}

long　long　MySqr(int　x)　{
　　return(x*x);　/*　返回值在括号中　*/
}