The atol () function in C

The function long int atol (const char * str) in the standard C library converts a string pointed to by parameter str to some long int.

Declare atol () function in C

Below is the declaration for the atol () function in C:

 long int atol ( const char * str ) 

Parameters

str - This is a string representing an integer.

Returns the value

This function returns an integer that has been converted as a long int value. If no valid conversion is performed, the function returns 0.

For example

The following program C illustrates the usage of the atol () function in C:

 #include #include #include int main () { long val ; char str [ 20 ]; strcpy ( str , "98993489" ); val = atol ( str ); printf ( "Gia tri duoi dang chuoi = %s, nGia tri duoi dang long int = %ldn" , str , val ); strcpy ( str , "QTM.com" ); val = atol ( str ); printf ( "nGia tri duoi dang chuoi = %s, nGia tri duoi dang long int = %ldn" , str , val ); return ( 0 ); } 

Compile and run the above C program to see the results.

According to Tutorialspoint

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