Getting Started with C programming-functions (bottom)

Meaning of void:

# include <stdio.h>int f (void)//void means no data is received, int means return int type value, that is, return 10 below; {return 10;//return 10 to the main function, that is, return 10 to the statement that is called in the function. A void before the}void g (void)//function name indicates that the function has no return value. {//return 10;//error, inconsistent with void above, cannot have return value. }int Main (void) {int i = 88;int J = 5201314;i = f ();//Because the F function does not receive any data, the parentheses are empty, and after the function is called, the F function returns the value of 10,i to 10. j = g (); Because the G function does not return a value, it cannot be assigned to J. Note: No return value is returned to 0, but it is returned as empty! printf ("%d\n", i);p rintf ("%d\n", j); return 0;}

The difference between break and return:

# include <stdio.h>void f (void) {int i;for (i=0; i<5; i++) {printf ("Hehe! \ n "); Break;//break is used to terminate the For loop. The}return;//return is used to terminate the entire function. printf ("Haha! \ n ");} int main (void) {f (); return 0;}

Function exercises--Multiple primes:

# include <stdio.h>//This function is to determine whether a number is a prime, if so, returns True, or False if not. BOOL IsPrime (int m) {int i;for (i=2; i<m; ++i) {if (0 = = m%i) break;} if (i = = m) return True;elsereturn false;} This function is to enter 1 to N of all prime numbers. void Traverseval (int n) {int i;for (i=2; i<=n; ++i) if (IsPrime (i)) printf ("%d\n", I);} int main (void) {int i;int val;int j;printf ("Please enter the number of times required:"), scanf ("%d", &i), for (j=1; j<=i; ++j) {printf ("Please enter the upper%d limit: ", j); scanf ("%d ", &val); Traverseval (val);} return 0;}

Global variables and local variables:

# include <stdio.h>int k = 1000;//k is a global variable that can be used by all functions. void f (int i) {int j;//parameter I and definition variable J are local variables, i.e. only for internal use of the function. printf ("k =%d\n", k);} int main (void) {int m = 10;f (m); return 0;}

Naming conflict issues for global variables and local variables:

# include <stdio.h>int i = 99;void f (int i) {printf ("i =%d\n", i);} int main (void) {F (8); return 0;} /* The output is: i = 8 that is, when the global variable name is the same as the local variable name, local variables, local variables (Private) Priority > Global Variables (public) are used by default. */

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Getting Started with C programming-functions (bottom)