C语言如何从指定行读取文件

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在这里我们一共有三个功能，写文件，读文件，从指定行中读取文件，代码比较简单不多加解释。

#include <stdlib.h>#include <string.h>#include <stdio.h>#define MAX_LENTH_OF_LINE 1024FILE* fptr;int WriteToText(){fptr = fopen("test.txt", "w");if (fptr == NULL){printf("Cannot Open file for writing\n");return -1;}for (int i = 0; i < 3; i++){fprintf(fptr, "%d %d %d %d %d %d \n", i + 1, i + 2, i + 3, i + 4, i + 5, i + 6);/*生成文本文件test.txt 文本内容1 2 3 4 5 62 3 4 5 6 73 4 5 6 7 8*/}fclose(fptr);return 1;}int ReadFromText(){fptr = fopen("test.txt", "r");if (fptr == NULL){printf("Cannot Open file for reading\n");return -1;}int a, b, c, d, e, f;for (int i = 0; i < 3; i++){fscanf(fptr, "%d %d %d %d %d %d \n", &a, &b, &c, &d, &e, &f);printf("%d %d %d %d %d %d \n", a, b, c, d, e, f);/*控制台打印出的文本内容1 2 3 4 5 62 3 4 5 6 73 4 5 6 7 8*/}fclose(fptr);return 1;}int SetPositionByLine(FILE *fp, int nLine){int i = 0;char buffer[MAX_LENTH_OF_LINE + 1];fpos_t pos;rewind(fp);for (; i < nLine; i++)fgets(buffer, MAX_LENTH_OF_LINE, fp);fgetpos(fp, &pos);return 0;}int ReadByLine(){char buffer[MAX_LENTH_OF_LINE + 1];FILE *fp;fp = fopen("test.txt", "r");SetPositionByLine(fp, 2);fgets(buffer, MAX_LENTH_OF_LINE, fp);printf("%s\n", buffer);/*读取第三行的内容3 4 5 6 7 8*/fclose(fp);}int splitLineStr(int strNum,char* bufIn,char* bufOut,int* bufLen){    int i = 0;    int j = 0;    int k = 0;    for (; bufIn[i] != 0 && j < strNum; i++){        if (isspace(bufIn[i])){            if (j == 0)            {                memcpy(bufOut, bufIn, i);                k = i + 1;                *bufLen = i;            }            else            {                memset(bufOut, '\0', sizeof(bufOut));                memcpy(bufOut, bufIn + k, i - k);                *bufLen = i - k;                k = i + 1;            }            j++;            if (j == strNum)            {                return 1;            }            else{                continue;            }        }    }    return 1;}void main(){//WriteToText();//ReadFromText();ReadByLine();system("pause");return;}

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