Detailed explanation and usage of the sprintf function in the C language

The sprintf function is a commonly used formatting output function in the C language, which is used to convert data into a specified format and store it in a character array.

The declaration of the function is as follows:

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

In this case, str is the character array storing the result, format is the formatting string, and … is the variable parameter list.

The usage of the sprintf function is as follows:

1. Convert the variable to a string.

int num = 10;
char str[10];
sprintf(str, "%d", num);
printf("str: %s\n", str);  // 输出：str: 10

In this example, convert the integer variable num to a string and store it in a character array str.

1. Format multiple variables for output.

int num1 = 10;
int num2 = 20;
char str[20];
sprintf(str, "num1: %d, num2: %d", num1, num2);
printf("%s\n", str);  // 输出：num1: 10, num2: 20

In this example, convert multiple variables num1 and num2 to strings using formatted strings, and store them in a character array named str.

1. Format floating point numbers for output

float num = 3.14;
char str[10];
sprintf(str, "%.2f", num);
printf("str: %s\n", str);  // 输出：str: 3.14

In this example, convert the floating point variable num to a string, keeping 2 decimal places, and store the result in the character array str.

It is important to note that the sprintf function carries the risk of buffer overflow, so it is crucial to ensure that the target character array is large enough to avoid data overflow. Additionally, the sprintf function returns the number of characters successfully converted and stored, returning a negative number if the storage fails.