c - How to calculate number of lines in file? -

i work in c-language @ first time , have question.

how can number of lines in file?

file *in; char c; int lines = 1; ... while (fscanf(in,"%c",&c)  == 1) {   if (c == '\n') {     lines++;   } } 

am right? don't know how moment , when string cross new line.

op's code functions aside maybe off-by-one issue , last line issue.

standard c library definition

a text stream ordered sequence of characters composed lines, each line consisting of 0 or more characters plus terminating new-line character. whether last line requires terminating new-line character implementation-defined. c11dr §7.21.2 2

a line ends '\n' , last line may or may not end '\n'.

if using idea last line of file not require final '\n, goal count number of occurrences character read after '\n'.

// let use wide type // start @ 0 file may empty unsigned long long line_count = 0;  int previous = '\n'; int ch; while ((ch = fgetc(in)) != eof) {   if (previous == '\n') line_count++;   previous = ch; }  printf("line count:%llu\n", line_count); 

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reading file 1 character @ time may less efficient other means, functionally meets op goal.

this answer uses (ch = fgetc(in)) != eof instead of fscanf(in,"%c",&c) == 1 typically ""faster", optimizing compiler, either may emit similar performance code. such details of speed can supported analysis or profiling. when in doubt, code clarity.