Question

can someone tell me what does this c code do?
#include #include int main(int argc, char *argv[]) { FILE *in; int c; assert(argc == 2); in = fopen(argv[1], "r"); assert(in); while ((c = fgetc(in)) != EOF) { if (c == '\n') { putchar('$'); } putchar(c); } return 0; }

Answer 1

One of the ways to figure out what a piece of code does is by splitting it into easier parts. You could split your example into three parts:

1)
assert(argc == 2);
in = fopen(argv[1], "r");
assert(in);

2)
while ((c = fgetc(in)) != EOF)

3)
if (c == '\n') { putchar('$'); } putchar(c);


You'll need to figure out what happens in 1, when the loop in 2 will stop and what will be done each iteration of the loop (3).