Difference between stdin and calling arguments?

Question

If I had a method

int main(int argc, char* argv[]) {

I am under the impression that calling arguments and receiving data through standard i

Answer 1

The difference is in how you access them.

Arguments are accessible through argv. Standard input is accessible through the stdin file descriptor.

case 1 - command line arguments:

int i;
for (i=1; i < argc; i++) {
    printf("%s", argv[i]);      // Prints "1 2 3 4"
}

case 2 - standard input:

char buffer[121];
while (scanf("%120s", buffer) == 1) {
    printf("%s", buffer);      // Prints "5 6 7 8"
}