C语言中怎样读取txt中指定的跨行字符串之间的字符？

RT，指定字符串一定是跨行的

我的代码是：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define N 100
#define SUCCESS 0

int main(){
FILE *fp;
char cBuf[N+1];
char cRes[40960] = {0};

}

按行读取后用strcat将各行连接到一个字符串中就行了。或者用fread读取

修改如下，供参考：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define N 100
#define SUCCESS 0
int test(char *pcBuf, char *pcRes);
int main(){
    FILE *fp;
    char cBuf[N+1];
    char cRes[40960] = {0};
    long lenght = 0;
    if( (fp=fopen("d:\\demo.txt","rt")) == NULL ){
         puts("Fail to open file!");
         //exit(0);
    }
    else{
         fseek(fp,0L,SEEK_END);
         lenght = ftell(fp);
         rewind(fp);
         fread(cBuf,1,lenght,fp);
         fclose(fp);
         printf("%s\n", cBuf);
         test(cBuf, cRes);
         printf("%s\n", cRes);
    }
    //while(fgets(cBuf, N, fp) != NULL){
         //printf("%s", cBuf);
         //test(cBuf, cRes);
         //printf("%s\n", cRes);
    //}
    //fclose(fp);
    return 0;
}
 
int test(char *pcBuf, char *pcRes)
{
     char *pcBegin = NULL;
     char *pcEnd = NULL;
     pcBegin = strstr(pcBuf, "hello");
     pcEnd = strstr(pcBuf, "yu");
     if(pcBegin == NULL || pcEnd == NULL || pcBegin > pcEnd)
     {
        printf("not found!\n");
     }
     else{
        pcBegin += strlen("hello ");//修改
        memcpy(pcRes, pcBegin, pcEnd-pcBegin);
     }
     return SUCCESS;
}