c语言学习

#include <stdio.h>
int a = 1;
void f(){
	a = 2;
	printf("在函数f的内部: a=%d",a);
	
}

int main(){
	f();
	printf("在函数main的内部: a=%d",a);
}

#include <stdio.h>
int a = 200;
void f(){
	int a = 1;
	a = 2;
	printf("%d\n",a);
	
}

int main(){
	f();
	printf("%d\n",a);
}

在main函数中，绝对不可能访问

f中的局部变量

此处的a就是全局变量a

#include <stdio.h>
int a = 200;
int b = 100;
void f(){
	int a = 1;
	b = 2;
	printf("a=%d,b=%d\n",a,b);
	
}

int main(){
	f();
	printf("a=%d,b=%d\n",a,b);
}

#include <stdio.h>
void f(int m){
	m += 10;
}
int main(){
	int m = 1;
	printf("m = %d\n",m);
	f(m);
	printf("m = %d\n",m);
}