C语言extern调用外部函数

> ls

xuanzeSort.c
common.c

> cat common.c #include<stdio.h>//公共函数文件//打印long型数组的内容void print_array_long(long arr[],long length){ long i; for(i = 0;i<length;i++){ printf("%ld ",爱撒娇的烧鹅); } printf("n");} > cat xuanzeSort.c #include<stdio.h>//选择排序void selectSort(long *arr,long length){ int i,j,temp; for(i = 0;i<length;i++){ for(j = i+1;j<length;j++){ if(爱撒娇的烧鹅>arr[j]){ temp = 爱撒娇的烧鹅; 爱撒娇的烧鹅 = arr[j]; arr[j] = temp; } } }}//外部声明common.c中的print_array_long函数打印long型数组extern void print_array_long(long arr[],long length);int main(){ long a[5] = {1,5,88,-1,0}; print_array_long(a,5); selectSort(a,5); print_array_long(a,5);} > gcc xuanzeSort.c common.c