C Language: Maths Inbuilt Functions 3

Conversion from one data type to another data type

atoi():

atoi converts a string to int.
header file : stdlib.h

atof():

atof converts a string to a floating point
header file : stdlib.h

atol():

Converts a string to a long
header file : stdlib.h

itoa():

itoa converts an integer to a string
header file : stdlib.h

ltoa():

ltoa converts a long to a string
header file : stdlib.h

ultoa():

ultoa converts an unsigned long to a string
header file : stdlib.h

/* example atoi()  */
#include <stdio.h>
#include<stdlib.h>

int main()
{
    int n,n1;

    // char *str = "12.67";
   char str[]="12.67";
    //   char str[10]="12.67";
   n = atoi(str);
   printf("string = %s integer = %d\n", str, n);
   n1=n*n;
   printf("square = %d\n",n1);
	return 0;
}

Output:

string = 12.67 integer = 12
square = 144

/* example of atof() */
#include <stdio.h>
#include<stdlib.h>

int main()
{
    float f,f1;
    // char *str = "12.67";
   char str[]="12.67";
   f = atof(str);
   printf("string = %s float = %f\n", str, f);
   f1=f*f;
   printf("square = %f\n",f1);
	return 0;
}

Output:

string = 12.67 float = 12.670000
square = 160.528900