Difference between fprintf, printf and sprintf?

Question

Can anyone explain in simple English about the differences between `printf`, `fprintf`, and `sprintf` with examples?What stream is it in?I'm really confused between the three of these while reading about "File Handling in C".

Answer 1

The printf function prints to the standard output:

x = 7;

printf("x=%d\n",x);

prints x=7 to your screen. printf is used to display data on the screen.

The fprintf function prints, but to a file instead of the screen. It takes an additional parameters, a pointer to a FILE type:

FILE *fptr = fopen("data.txt","w+");

x = 7;

fprintf(fptr,"x=%d\n",x);

fclose(fptr);

Your output will be in the file data.txt. fprintf() is used for such things as creating reports, saving data values for the next time a program runs, etc.

The sprintf function doesn't exactly print, but instead puts the formatted output into a string buffer:

char output[200];

x = 7;

sprintf(output,"x=%d",x);

If you dump (ie, print) the contents of output, you'll find it contains "x=7". sprintf is often used to create formatted strings which can then be displayed, save to files, put into structures, etc. One common use is as a means to convert one type of data (int, float, etc) into string..