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Tutorials > C Programming > Standard Library Functions

Standard Library Functions

The C Standard Library is a collection of functions and macros that provide standard and generic functions for tasks such as input/output, string manipulation, memory allocation, and more. The functions in the C Standard Library are declared in various header files, such as stdio.h, string.h, and stdlib.h, and are available for use in your C programs.

Here are some examples of commonly used C Standard Library functions:

  • printf - The printf function is used to print formatted text to the standard output (usually the screen). For example:
c
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#include <stdio.h>

int main() {
    printf("Hello, world!\n");
    return 0;
}
  • scanf - The scanf function is used to read formatted input from the standard input (usually the keyboard). For example:
c
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#include <stdio.h>

int main() {
    int a;
    printf("Enter an integer: ");
    scanf("%d", &a);
    printf("You entered: %d\n", a);
    return 0;
}
  • strlen - The strlen function returns the length of a null-terminated string. For example:
c
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#include <string.h>
#include <stdio.h>

int main() {
    char str[] = "Hello, world!";
    int len = strlen(str);
    printf("The length of the string is: %d\n", len);
    return 0;
}
  • malloc - The malloc function is used to dynamically allocate memory at runtime. For example:
c
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#include <stdlib.h>
#include <stdio.h>

int main() {
    int n = 5;
    int *ptr = (int *) malloc(n * sizeof(int));
    if (ptr == NULL) {
        printf("Memory allocation failed.\n");
        return 1;
    }
    int i;
    for (i = 0; i < n; i++) {
        ptr[i] = i * i;
    }
    printf("The squares of the first %d integers are: ", n);
    for (i = 0; i < n; i++) {
        printf("%d ", ptr[i]);
    }
    printf("\n");
    free(ptr);
    return 0;
}

These are just a few examples of the many functions available in the C Standard Library. By using these functions, you can write powerful and efficient C programs with less code and effort.



Next: Error Handling

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