问如何查找一个文件的行数？

EN

#include <stdio.h>
#include <stdlib.h>

#define CHARBUFLEN 8

int main (int argc, char **argv) {
    int c, lineCount, cIdx = 0;
    char buf[CHARBUFLEN];
    FILE *outputPtr;

    outputPtr = popen("wc -l data_1.txt", "r");
    if (!outputPtr) {
        fprintf (stderr, "Wrong filename or other error.\n");
        return EXIT_FAILURE;
    }

    do {
        c = getc(outputPtr);
        buf[cIdx++] = c;
    } while (c != ' ');
    buf[cIdx] = '\0';
    lineCount = atoi((const char *)buf);        

    if (pclose (outputPtr) != 0) {
        fprintf (stderr, "Unknown error.\n");
        return EXIT_FAILURE;
    }

    fprintf (stdout, "Line count: %d\n", lineCount);

    return EXIT_SUCCESS;
}