Question

I apologize for this seemingly relatively simple task that I can’t figure out. I wasn’t able to seem to find a way to write data to a new row in a .csv file using the C language. I’m saving 3 variables to the .csv file, and currently they will always replace A1:C1. Here is my print commands:

fs = fopen("C:\\Documents and Settings\\ajkaas\\Desktop\\110c.csv", "w");
if(fs == NULL){
    printf("Couldn't open file\n");
    return;
}
fprintf(fs, "%u,%11.8f,%11.8f\n", message63->rcvrBitErrorCount,
(double)message63->rcvrTotalBitErrorCount / (double)(message63->rcvrBlockIndex * message63->rcvrBitsPerBlock),
(double)message63->rcvrBlockErrorCount / (double)(message63->rcvrBlockIndex));
fclose(fs);

I know that looks messy, and I apologize for that as well. I was looking at some documentation but couldn’t seem to find an answer. Every time the for loop runs that this code is in, my A1:C1 rows are replaced but I want it to drop down a row every time the loop runs again. Does that make any sense? Let me know if you need anything additional and thank you.

Answer 1

You need to open the file in append mode. Change the second parameter to fopen from “w” to “a”.