getline(file, str) reads an entire line from file into string str, including spaces. It stops at the newline character (consuming it but not storing it). This beats >> for reading sentences or formatted text.
Common pattern: while(getline(file, line)) { process(line); }. The loop continues until reaching end-of-file. Each iteration gives you one complete line to parse or display. You can specify a custom delimiter: getline(file, str, ',') reads until a comma instead of newline.
This parses CSV files where commas separate values. The delimiter is consumed but not included in str.