C语言 文件操作

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <ctype.h>int main(void) {    static int a[100], a2[100];    FILE * fp1;    FILE * fp2;    FILE * fp3;    int num, i;    int index = 0;    float fnum = 1.0f / 7.0f, fnum2 = 0.0;    if ((fp1 = fopen("C:\\1.txt", "r")) == NULL) {        puts("File 1.txt cannot be opened !");        exit(1);    }    if ((fp2 = fopen("C:\\2.txt", "w+")) == NULL) {        puts("File 2.txt cannot be opened !");        exit(1);    }    if ((fp3 = fopen("C:\\3.bin", "wb+")) == NULL) {        puts("File 3.bin cannot be opened !");        exit(1);    }    while (fscanf(fp1, "%d", &num) == 1) {        a[index++] = num;        fprintf(fp2, "%d ", num);    }    /* ungetc(' ', fp2); */    putc('\n', fp2);    fputs("Hello file1 !", fp2);    printf("The offset of fp1 is: ");    printf("%d\n", ftell(fp1));    printf("The offset of fp2 is: ");    printf("%d\n", ftell(fp2));    fseek(fp1, 0L, SEEK_SET);    fseek(fp2, 0L, SEEK_SET);    /*    for (i = 0; i < index; i++) {        printf("%d ", a[i]);    }    putchar('\n');    */    if (fwrite(a, index * sizeof(int), 1, fp3) != 1) {        puts("fwrite error !");        exit(1);    }    fseek(fp3, 0L, SEEK_SET); /* 还原fp3 */    if (fread(a2, sizeof(int), index, fp3) != index) {        puts("fread error !");        exit(1);    }    puts("The integers read from fp3 is: ");    for (i = 0; i < index; i++) {        printf("%d ", a2[i]);    }    putchar('\n');    fseek(fp3, 0L, SEEK_END);    if (fwrite(&fnum, sizeof(float), 1, fp3) != 1) {        puts("The float number cannot be writen to the file !");        exit(1);    }    fseek(fp3, -1L * sizeof(float), SEEK_END);    if (fread(&fnum2, sizeof(float), 1, fp3) != 1) {        puts("The float number in the file is failed to read !");        exit(1);    }    printf("%.7f\n", fnum2);    fclose(fp1);    fclose(fp2);    fclose(fp3);    return 0;}