Question

FILE *ExcelFile = fopen("testdata.csv","w");
if (ExcelFile == NULL)
    return -1;
fprintf(ExcelFile,"1 2 3");

fprintf(ExcelFile,"\n");
fclose(ExcelFile);

//==============================================
FILE *fa = fopen("testdata.csv","w");
if (fa == NULL)
    return -1;
fseek (fa, 6 , SEEK_SET );
fprintf(ExcelFile,"a");


fclose(fa);

in the code i have write 1 2 3 in the file and also inserted ‘\n’ (required for the program) now i want to place a after 3 like 1 2 3 a but hte problem iam facing is that my code erase all char an simply write a . help required .thanks

Answer 1

You want mode “r+”. Using mode “a”, all writes will go to the end of the file.