printf

printf函数用于在标准输出控制台上打印数据的字符流。
    语法：

int printf(const char* str, ...);

示例：

// simple print on stdout
#include<stdio.h>
int main()
{
printf("hello geeksquiz");
return 0;
}

输出：

hello geeksquiz

sprintf

语法：

int sprintf(char *str, const char *string,...);

字符串打印函数（sprintf）代替控制台上的打印，将其存储在sprintf中指定的char缓冲区中。
    示例：

// Example program to demonstrate sprintf()
#include<stdio.h>
int main()
{
	char buffer[50];
	int a = 10, b = 20, c;
	c = a + b;
	sprintf(buffer, "Sum of %d and %d is %d", a, b, c);

	// The string "sum of 10 and 20 is 30" is stored
	// into buffer instead of printing on stdout
	printf("%s", buffer);

	return 0;
}

输出：

Sum of 10 and 20 is 30

fprintf

fprintf用于打印文件中的字符串内容，但不能在标准输出控制台上打印。

int fprintf(FILE *fptr, const char *str, ...);

示例：

#include<stdio.h>
int main()
{
	int i, n=2;
	char str[50];

	//open file sample.txt in write mode
	FILE *fptr = fopen("sample.txt", "w");
	if (fptr == NULL)
	{
		printf("Could not open file");
		return 0;
	}

	for (i=0; i<n; i++)
	{
		puts("Enter a name");
		gets(str);
		fprintf(fptr,"%d.%s\n", i, str);
	}
	fclose(fptr);

	return 0;
}

运行程序：

输入: GeeksforGeeks
       GeeksQuiz
输出 :  sample.txt file now having output as 
0. GeeksforGeeks
1. GeeksQuiz

参考文档

[1]Vankayala Karunakar.What is the difference between printf, sprintf and fprintf?[EB/OL].https://www.geeksforgeeks.org/difference-printf-sprintf-fprintf/,2018-12-13.