c语言读写文件实例，读大量数据时据说还是c语言效率高，比c++的fstream快...留存。
#include <stdio.h>#include <stdlib.h>FILE *f;int i;int v;int n;int m[100000];int compare(const void *a,const void *b) { return (*((int *)a)) - (*((int *)b));}int main() { f=fopen("D:\\number.txt","r"); if (NULL==f) { printf("Can not find file D:\\number.txt!\n"); return 1; } i=0; while (1) { if (feof(f)) break; if (1==fscanf(f,"%d",&v)) { m[i]=v; i++; if (i>=100000) break; } else { fscanf(f,"%*c"); } } fclose(f); n=i; qsort(m, n, sizeof(int), compare); f=fopen("D:\\result.txt","w"); if (NULL==f) { printf("Can not create file D:\\result.txt!\n"); return 1; } for (i=0;i<n;i++) fprintf(f,"%d\n",m[i]); fclose(f); return 0;}