What is the usage of cout in the C language?

In the C language, cout is not a valid keyword or identifier. cout is an output stream object in C++ used to output data to the console. In C language, you can use the printf function to achieve similar functionality. Here is an example:

#include <stdio.h>

int main() {
   int num = 10;
   printf("The number is: %d\n", num);
   return 0;
}

The output result is:

The number is: 10

In the C language, the printf function is used for formatted output, specifying the data type to be output by using placeholders (such as %d). Multiple placeholders can be used to output the values of multiple variables.