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C stdio.h Functions
Explore all C stdio.h functions in one place with clear descriptions, example programs, and outputs. Learn printf, scanf, file handling functions, and more for fast and effective C programming.
| Function |
Description |
Example Code |
Output |
|---|---|---|---|
|
printf() |
Prints formatted output to the console |
printf("Hi %d",10); |
Hi 10 |
|
scanf() |
Reads formatted input from user |
scanf("%d",&n); |
User enters: 25 |
|
getchar() |
Reads one character from user input |
char c=getchar(); |
User enters: A |
|
putchar(ch) |
Outputs a single character to console |
putchar('X'); |
X |
|
puts(str) |
Prints a string + newline |
puts("Hello"); |
Hello |
|
getc(fp) |
Same as fgetc() |
ch=getc(fp); |
e.g., H |
|
putc(ch,fp) |
Same as fputc() |
putc('B',fp); |
B written |
|
fopen("file","mode") |
Opens a file and returns a file pointer |
fp=fopen("data.txt","w"); |
(File opened) |
|
fclose(fp) |
Closes an open file |
FILE *fp=fopen("a.txt","r"); fclose(fp); |
(File closed successfully) |
|
fgetc(fp) |
Reads a single character from file |
ch=fgetc(fp); |
e.g., A |
|
fgets(str,n,fp) |
Reads a line/string from file |
fgets(str,50,fp); |
e.g., Hello world |
|
fputc(ch,fp) |
Writes a character into a file |
fputc('A',fp); |
A written |
|
fputs(str,fp) |
Writes a string into a file |
fputs("Hello",fp); |
Hello written |
|
fprintf(fp, "text") |
Writes formatted text into file |
fprintf(fp,"Age=%d",20); |
(Written to file) |
|
fscanf(fp,"%d",&x) |
Reads formatted data from a file |
fscanf(fp,"%d",&num); |
e.g., 10 |
|
fread(ptr,size,n,fp) |
Reads block of data from file |
fread(a,sizeof(int),5,fp); |
(Reads array) |
|
fwrite(ptr,size,n,fp) |
Writes block of data to file |
fwrite(a,sizeof(int),5,fp); |
(Writes array) |
|
fseek(fp, offset, origin) |
Moves file pointer |
fseek(fp,0,SEEK_END); |
(Pointer moved) |
|
ftell(fp) |
Returns current file position |
printf("%ld",ftell(fp)); |
e.g., 20 |
|
rewind(fp) |
Moves pointer to file beginning |
rewind(fp); |
Position = 0 |
|
feof(fp) |
True if end of file reached |
while(!feof(fp)) { fgetc(fp); } |
(EOF detected) |
|
ferror(fp) |
True if a file error occurred |
if(ferror(fp)) printf("Error"); |
Error (if error exists) |
|
remove("file") |
Deletes a file |
remove("a.txt"); |
(File deleted) |
|
rename("old","new") |
Renames a file |
rename("a.txt","b.txt"); |
(Renamed) |
|
snprintf(str,n,"fmt") |
Safe formatted output to array |
snprintf(str,10,"Hi %d",5); |
Hi 5 |
|
sprintf(str,"fmt") |
Writes formatted output to array |
sprintf(str,"Age=%d",20); |
Age=20 |
