c语言中全局变量的使用

#include <stdio.h>

void func1(){

    x += 10;

    y += 20;

    printf("函数:%s  中 x = %d   y = %d \n",__FUNCTION__,x,y);

}

int x = 10;

int y = 20;

void func2(){

    x += 10;

    y += 20;

    printf("函数:%s  中 x = %d   y = %d \n",__FUNCTION__,x,y);

}

int main(){

    func1();

    func2();

    printf("函数:%s  中 x = %d   y = %d \n",__FUNCTION__,x,y);

    return 0;

}

/*

输出：

main.cpp: In function ‘void func1()’:

main.cpp:6:5: error: ‘x’ was not declared in this scope

    6 |     x += 10;

      |     ^

main.cpp:7:2: error: ‘y’ was not declared in this scope

    7 |  y += 20;

      |  ^

*/