二十五岁时我们都一样愚蠢、多愁善感,喜欢故弄玄虚,可如果不那样的话,五十岁时也就不会如此明智。
标题:C库宏 NULL()
C库宏 NULL()
#include <stddef.h> #include <stdio.h> int main () { FILE *fp; fp = fopen("file.txt", "r"); if( fp != NULL ) { printf("Opend file file.txt successfully\n"); fclose(fp); } fp = fopen("nofile.txt", "r"); if( fp == NULL ) { printf("Could not open file nofile.txt\n"); } return(0); }