C PR0gramming..

Neeeed 'C' Help.

I need to read in input from the command line argument and open the text file ( 2nd arguement; nums1.txt in this case)
ie:  ./shitprogram nums1.txt

and so what would i be inputting here:
fopen("????","r");

I know that argv[1] = "nums1.txt" but how would i use this as a variable in fopen() ?


#include <stdio.h>
int main(int argc, char** argv) {
    if(argc<2) {
        fprintf(stdio, "usage: %s filename\n", argv[0]);
    }
    int nig;
    FILE* fp = fopen(argv[1], "r");
    fscanf(fp, "%d", &nig);
    fclose(fp);
    return nig;
}