c - 在 C 中给定一个文件名，如何读取每行只有 75 个字符？

Question

假设我有一个包含以下内容的文件:

This line contains more than 75 characters due to the fact that I have made it that long. 
Testingstring1
testingstring2

这是我的代码:

void checkLine( char const fileName[]){
    FILE *fp = fopen(fileName,"r");
    char line[75];
    while (1) {
        fgets(line,75,fp);
        if (feof(fp)){
            break;
        } else {
            printf("%s\n", line);
        }
    }
}

如何让它只保存变量 line 中每行的前 75 个字符？

上面的代码给出了以下输出:

This line contains more than 75 characters due to the fact that I have mad
e it that long.

Testingstring1

testingstring2

预期的输出应该是这样的:

This line contains more than 75 characters due to the fact that I have mad
Teststring1
Teststring2

Answer 1

最大 strlen 将为 74。

bool prior_line_ended = true;
while (1) {
    fgets(line, 75, fp);
    if (feof(fp)){
        break;
    }

    // Remove any line end:

    char* pos = strchr(line, '\n');
    //char* pos = strchr(line, '\r');
    //if (pos == NULL) {
    //    pos = strchr(line, '\n');
    //}
    bool line_ended = pos != NULL;
    if (line_ended) {
        *pos = '\0';
    }

    // Output when starting fresh line:

    if (prior_line_ended) {
        printf("%s\n", line);
    }
    prior_line_ended = line_ended;
}